Police block the street after three persons have been hurt in a knife attack at Paris prefecture de police (police headquarters) on October 3, 2019. (Photo by Martin BUREAU / AFP) (Photo by MARTIN BUREAU/AFP via Getty Images)
Police block the street after three persons have been hurt in a knife attack at Paris prefecture de police (police headquarters) on October 3, 2019. (Photo by Martin BUREAU / AFP) (Photo by MARTIN BUREAU/AFP via Getty Images)
PHOTO: Martin Bureau/AFP/Getty Images
Now playing
01:18
Knife attacker shot dead inside Paris police headquarters
PHOTO: Indonesia Search and Rescue Agency
Now playing
02:09
Woman who is trapped underneath earthquake's rubble captured on video
Barrie
Barrie's aunt speaks about how the police brought her the news about the death of her nephew Ibrahima.
PHOTO: VTM
Now playing
01:26
Aunt of Black man who died after arrest in Belgium: We want justice
screengrab US social media
screengrab US social media
PHOTO: Getty Images
Now playing
04:35
Tech companies ban Trump, but not other problematic leaders
WASHINGTON, DC - JANUARY 13:  Speaker of the House Nancy Pelosi (D-CA) presides over the vote to impeach U.S. President Donald Trump for the second time in little over a year in the House Chamber of the U.S. Capitol January 13, 2021 in Washington, DC. The House voted to impeach Trump on the charge of "incitement of insurrection," 232-197 after a mob of his supporters attacked the U.S. Capitol where Congress was working to certify the Electoral College victory of President-elect Joe Biden on January 6. 10 Republicans voted to impeach. (Photo by Chip Somodevilla/Getty Images)
WASHINGTON, DC - JANUARY 13: Speaker of the House Nancy Pelosi (D-CA) presides over the vote to impeach U.S. President Donald Trump for the second time in little over a year in the House Chamber of the U.S. Capitol January 13, 2021 in Washington, DC. The House voted to impeach Trump on the charge of "incitement of insurrection," 232-197 after a mob of his supporters attacked the U.S. Capitol where Congress was working to certify the Electoral College victory of President-elect Joe Biden on January 6. 10 Republicans voted to impeach. (Photo by Chip Somodevilla/Getty Images)
PHOTO: Chip Somodevilla/Getty Images
Now playing
02:35
How the world is reacting to Trump's second impeachment
Indonesia sriwijay air crash search for victims wang pkg intl hnk vpx_00000920.png
Indonesia sriwijay air crash search for victims wang pkg intl hnk vpx_00000920.png
Now playing
02:21
Family members wait in anguish as search for crash victims continues
africa china coronavirus vaccine diplomacy lu stout pkg vpx _00025522.png
africa china coronavirus vaccine diplomacy lu stout pkg vpx _00025522.png
PHOTO: CCTV
Now playing
03:09
How China is hoping to use its vaccine as a diplomatic tool
PHOTO: CIRO FUSCO/AFP/ANSA/AFP via Getty Images
Now playing
00:38
Huge sinkhole appears in Italian hospital parking lot
TOPSHOT - Rescue workers carry recovered debris at the port in Jakarta on January 10, 2021, during the search operation for Sriwijaya Air flight SJY182 which crashed after takeoff from Jakarta on January 9. (Photo by Dany Krisnadhi / AFP) (Photo by DANY KRISNADHI/AFP via Getty Images)
TOPSHOT - Rescue workers carry recovered debris at the port in Jakarta on January 10, 2021, during the search operation for Sriwijaya Air flight SJY182 which crashed after takeoff from Jakarta on January 9. (Photo by Dany Krisnadhi / AFP) (Photo by DANY KRISNADHI/AFP via Getty Images)
PHOTO: Dany Krisnadhi/AFP/Getty Images
Now playing
02:16
Indonesian jetliner crashes after taking off from Jakarta
 HONG KONG PRO DEMOCRACY ACTIVIST VENTUS LAU BEING ESCORTED BY POLICE.
HONG KONG PRO DEMOCRACY ACTIVIST VENTUS LAU BEING ESCORTED BY POLICE.
PHOTO: VENTUS LAU FACEBOOK PAGE/Reuters
Now playing
03:15
See Hong Kong police arrest former pro-democracy lawmakers
Tensions between the United States and Iran are likely to further escalate once again after Tehran seized a South Korean-flagged chemical tanker in the Persian Gulf, according to semi-official Iranian news agencies, and announced it had resumed enriching uranium to 20% purity, far beyond the limits laid out in the 2015 nuclear deal. President Donald Trump walked away from the agreement in 2018. CNN
Tensions between the United States and Iran are likely to further escalate once again after Tehran seized a South Korean-flagged chemical tanker in the Persian Gulf, according to semi-official Iranian news agencies, and announced it had resumed enriching uranium to 20% purity, far beyond the limits laid out in the 2015 nuclear deal. President Donald Trump walked away from the agreement in 2018. CNN's Paula Hancocks reports.
PHOTO: YJC
Now playing
02:37
Footage shows chemical tanker seized by Iranian forces
A European health worker prepares a shot of the coronavirus vaccine.
A European health worker prepares a shot of the coronavirus vaccine.
PHOTO: Reuters
Now playing
02:14
Frustration in Europe over pace of coronavirus vaccine rollout
Jack Ma, the co-chair of the UN High-Level Panel on Digital Cooperation, founder of Alibaba Group, attends the Bund Summit in Shanghai. He says that the essence of finance is credit management. We must change the pawnshop idea of Finance and rely on the credit system. Shanghai, China, 24 October 2020.

Jack Ma, the co-chair of the UN High-Level Panel on Digital Cooperation, founder of Alibaba Group, attended the Bund Summit in Shanghai. He says that the essence of finance is credit management. We must change the pawnshop idea of Finance and rely on the credit system.No Use China. No Use France.
Jack Ma, the co-chair of the UN High-Level Panel on Digital Cooperation, founder of Alibaba Group, attends the Bund Summit in Shanghai. He says that the essence of finance is credit management. We must change the pawnshop idea of Finance and rely on the credit system. Shanghai, China, 24 October 2020. Jack Ma, the co-chair of the UN High-Level Panel on Digital Cooperation, founder of Alibaba Group, attended the Bund Summit in Shanghai. He says that the essence of finance is credit management. We must change the pawnshop idea of Finance and rely on the credit system.No Use China. No Use France.
PHOTO: Zhao Yun/Oriental Image/Reuters
Now playing
03:05
Chinese tech tycoon has not been seen in months
Now playing
02:19
Country has 2nd highest Covid-19 cases. See their vaccine plan
Swedish environmentalist Greta Thunberg arrives for a meeting at the Europa building in Brussels on March 5, 2020. (Photo by Kenzo TRIBOUILLARD / AFP) (Photo by KENZO TRIBOUILLARD/AFP via Getty Images)
Swedish environmentalist Greta Thunberg arrives for a meeting at the Europa building in Brussels on March 5, 2020. (Photo by Kenzo TRIBOUILLARD / AFP) (Photo by KENZO TRIBOUILLARD/AFP via Getty Images)
PHOTO: KENZO TRIBOUILLARD/AFP/Getty Images
Now playing
01:24
Greta Thunberg urges public to listen to the experts (2020)
Now playing
01:00
Boris Johnson condemns Trump's actions
Bystanders and a soldier stand near a damaged portion of the airport of Yemen
Bystanders and a soldier stand near a damaged portion of the airport of Yemen's southern city of Aden's after an explosion, Wednesday, Dec. 30, 2020. The blast struck the airport building shortly after a plane carrying the newly formed Cabinet landed on Wednesday. No one on the government plane was hurt. (AP Photo/Majid Saleh)
PHOTO: Majid Saleh/AP
Now playing
02:27
See moment of deadly explosion at Yemen airport
(CNN) —  

The perpetrator of a knife attack that left four people dead at a Paris police headquarters had recently adhered to a “radical vision of Islam,” according to witnesses, anti-terrorism prosecutor Jean-François Ricard said Saturday.

Three policemen and a female police administrative worker were killed Thursday by a colleague who was later shot dead by a 24-year-old police intern inside the building near Notre Dame Cathedral, the prosecutor said.

The attacker, identified by police only as Mickaël H., had converted “about 10 years ago” to Islam and recently had kept to a more “radical vision,” Ricard said during a news conference.

The attacker had contacts with people suspected of belonging to the ultraconservative Salafist movement of Islam, the prosecutor said.

The attacker had expressed his support for the 2015 Charlie Hebdo attacks, Ricard said, and “certain acts committed in the name of this religion,” as well as a desire to “cease certain forms of contact with women” and his adoption of traditional Muslim clothing “in the last few months.”

Wife remains in custody

The attacker and his wife exchanged 33 text messages over 29 minutes the morning preceding the attack, and their content was “exclusively religious,” the prosecutor said.

The last exchange ended with “Allahu akbar,” which means “God is greater” in Arabic, and “follow the vision of our prophet Mohammed and meditate over the Quran.”

These text messages were sent 30 minutes before the attacker visited a local store and bought two knives that would be used in the attack.

The attacker’s wife is still in police custody, the order for which was extended on Saturday afternoon for another 48 hours. She wasn’t designated as “Fichier S,” which French law enforcement use for a person who represents a serious threat to national security, Ricard said.

The attacker, who was deaf after contracting meningitis, was born in 1974 and worked in IT maintenance for French Police Intelligence at the Prefecture de Police.

He had no criminal record, the prosecutor said.

CNN’s Sandrine Amiel in Paris contributed to this report.