(CNN) -- A North Carolina man charged with killing a pregnant Fort Bragg soldier was the father of her unborn child, authorities said Wednesday.
Sgt. Edgar Patino faces first-degree murder charges in the slaying of Megan Touma.
Army Sgt. Edgar Patino is linked to two anonymous "confession" letters sent in what police believe was an attempt to derail the investigation into Megan Touma's death, police said.
Patino, 27, was arrested at his Hope Mills, North Carolina, home Tuesday night without incident. Patino, who is stationed at Fort Bragg's JFK Special Warfare Training Center, faces first-degree murder charges in the slaying of Touma, 23, who was seven months pregnant.
Touma's decomposing body was found in the bathtub of a hotel room near Fort Bragg on June 21. Authorities said Wednesday that they believe she died late June 13 or early June 14.
Although her death has been ruled a homicide, authorities said Wednesday that the state medical examiner has not made a final determination of how she died. Watch officials discuss the case »
Patino has admitted being in Touma's hotel room June 13, and investigators found that the room's electronic key card was last used on that day, police said Wednesday. However, Patino has not admitted killing Touma.
Patino wore red jail coveralls in his initial court appearance Wednesday afternoon. He spoke only to answer the judge's questions, acknowledging that he understood he was charged with first-degree murder and that the charge carries a maximum penalty of death or life in prison without parole. He also requested that an attorney be appointed for him.
Fayetteville, North Carolina, police Chief Tom Bergamine said Wednesday that Patino, who is married, was the father of Touma's fetus.
Police also said evidence links Patino to a letter received June 25 by the Fayetteville Observer newspaper. In it, the writer claimed to have killed Touma and said more killings were planned. The letter was signed with a circular symbol similar to one used by the Zodiac killer in California in the late 1960s.
At the request of police, the newspaper withheld information regarding the letters and delayed publishing a story for several days to allow police to conduct an investigation, Bergamine said.
Police also received a similar letter. Fayetteville police Sgt. Chris Corcione said both letters were postmarked June 24 and sent from Fayetteville. Patino purchased a typewriter the day before the letters were sent, Corcione said. That typewriter is now in police custody.
Police, however, stopped short of saying Patino wrote the letters, saying only that evidence links him to them.
Two of Touma's friends, who are also female soldiers and asked not to be named because they are not authorized to speak publicly about the case, said Touma and Patino had been stationed together in Germany and had dated. They said Patino had proposed to Touma in Germany, but when the two returned to North Carolina, she discovered that he was married.
Police said Wednesday that Patino was a person of interest from the early days of their investigation. Corcione said his initial interview with authorities could be described as "deceptive," and officials had little other contact with him until his arrest. Police have found no criminal record for him.
"We felt like from the beginning, there was no major concerns of a serial killer being out there," Bergamine said.
Patino was being held without bail at the Cumberland County Detention Center, Bergamine said.
Asked what police believe the motive to be, Fayetteville police Detective Joshua Carter said, "Right now, the motive is going to be held close. There's still several months of investigation left to be conducted."
"I think one of the things that folks need to understand is that scientific evidence, things that have to go to the lab, they're going to take time," Bergamine said. "This is not the world of television and 'CSI.' Things don't get settled within a hour."
Touma, a five-year Army veteran, had served with the U.S. Army Dental Activity Clinic in Bamberg, Germany, and in Fort Drum, New York, before her stint at Fort Bragg.
She is the second female soldier from Fort Bragg to die under suspicious circumstances since June.
Army 2nd Lt. Holley Wimunc was killed in early July. Her Fayetteville apartment was torched July 10, and her charred body was found nearby a few days later.
Her husband, Marine Cpl. John Wimunc, was charged with arson and first-degree murder in connection with the death. Another Marine, Lance Cpl. Kyle Alden, was charged with arson and felony accessory after the fact to first-degree murder.
Camp Lejeune, North Carolina, also had a homicide case involving a female service member this year. The charred body of Marine Lance Cpl. Maria Lauterbach, 20, was found in the backyard of another Marine stationed at the base, Cpl. Cesar Laurean. Lauterbach was eight months pregnant when she died.
Laurean, who has been charged with first-degree murder, was arrested in Mexico in April, but because he holds citizenship in the United States and Mexico, he cannot be immediately deported and must go through an extradition process.
Authorities have said that if he chooses to fight extradition, it could take two years to return him to North Carolina.
CNN's Marylynn Ryan contributed to this report.