(CNN) -- Relatives of 10-year-old Lyric Cook and 8-year-old Elizabeth Collins got news Monday that no family wants.
Authorities identified the bodies found by hunters in a wooded area last week as those of the two young Iowa cousins, missing since July. Their bodies were found in the Seven Bridges Wildlife Area in Bremer County.
Chief Kent Smock of the Evansdale, Iowa, Police Department, confirmed the news and said that the girls' families had been notified, according to a statement from the Black Hawk County Sheriff's Office.
The cause of the death in both cases is pending.
"Our hearts and prayers go out to the families and friends of those precious little girls," said Black Hawk County Sheriff Tony Thompson.
He vowed vigilance in pursuit of those responsible, and said no resource would be spared so that "justice may prevail."
Lyric and Elizabeth were last seen by their grandmother on July 13 when they left for a bike ride. The girls' bicycles and a purse were found near Meyers Lake in Evansdale, hours after they were reported missing.
A search of the 25-acre lake turned up nothing, and authorities eventually said they believed that the cousins had been abducted.
About a week after the girls disappeared, investigators said they thought Lyric and Elizabeth were alive.
FBI spokeswoman Sandy Breault declined then to say exactly what evidence they had to push them toward that conclusion, urging anyone with information to come forward.
A $50,000 reward was offered for information leading to the successful recovery of the girls and the prosecution of the person, or people, responsible.
The girls' disappearance sparked a massive volunteer search effort in Evansdale, a town of about 4,700 that is about 12 miles southeast of Cedar Falls.
Last week, when the bodies were found but authorities had not yet identified them as belonging to the girls, residents gathered at Meyers Lake for a candlelight vigil, according to CNN affiliate KCRG.
"I guess I'm not surprised ... because of the length of time that they've been missing," Karen Carroll told the network.
Carroll works at Poyner Elementary, where Elizabeth was in fourth grade. She said keeping morale up at the school has been tough.
Students and staff created a "remembrance chain" that they will give to the girls' families, along with a memorial made from pink ribbons. The chain is built from rings of colored construction paper.
Elizabeth's mother, Heather Collins, posted a message on Facebook last week expressing gratitude for the prayers and outpouring of support amid the "gut-wrenching news."
"We know that they are up in heaven with our savior," she wrote. "Lord we know that you have them in your loving arms and we are so blessed."
CNN's Mark Morgenstein and Chandler Friedman contributed to this report.