NEW ORLEANS, Louisiana (CNN) -- Hundreds of officers, some from as far away as Colorado, turned out Friday along with New Orleans residents to mourn slain police officer Nicola Cotton -- whose violent death has shaken the city.
Officer Nicola Cotton was shot to death by a man who fit the description of a rape suspect.
An autopsy showed Cotton, 24, was eight weeks pregnant when she was killed.
On Monday, she stopped a man matching the description of a rape suspect, and a struggle ensued as she tried to arrest him.
The man, 44-year-old Bernel Johnson, grabbed Cotton's baton and beat her, New Orleans police said.
Surveillance video showed him grabbing her service weapon, a .40-caliber Glock, and shooting her 15 times in the head and body.
Johnson waited until police arrived on the scene and gave them the firearm.
On Friday, mourners formed a line snaking around the block as they waited to file past Cotton's flag-draped coffin.
At her funeral, friends and fellow officers remembered her as a having a huge heart.
"Few are willing to do the job Officer Cotton did, and few can," said police Superintendent Warren Riley.
A letter from Cotton's partner was read by another officer at the service. "I know I can't bring you back," it said. "I wish I could have been with you on that day."
Cotton was in the first police academy graduating class after Hurricane Katrina. She had relocated to Memphis, Tennessee, but chose to return to New Orleans, relatives said.
When she responded to the call of a possible rape suspect on the loose about 10 a.m. Monday, Cotton was patrolling alone in her cruiser.
In the wake of her death, many in New Orleans questioned why she was alone in the 6th District, the city's deadliest. There were 209 murders in New Orleans last year, many of them in the 6th District.
Police spokesman Joe Narcisse said the practice is common in the city, and Cotton did nothing wrong in approaching the suspect -- who was twice her size -- by herself.
"She was doing what we pay her to do, what we beg of [officers] to do," Narcisse said.
Johnson has been charged with first-degree murder and is scheduled to appear in court February 19.
He was involuntarily committed three weeks before he encountered Cotton. Deputy psychiatric coroner Jeffery Rouse said in his opinion, Johnson is a paranoid schizophrenic with violent tendencies. Watch an examination of why a mental patient slipped through the cracks »
But the mental health system in New Orleans -- which is still struggling to rebuild and recover after the 2005 storm -- is broken, Rouse said.
"It's the same exact story, and it reads: 'Person with severe mental illness. Brought in by police. Not taking medication. Homeless.' I've written that phrase till my fingers fall off," he said.
"The fact of the matter is, until all the systems get together and have the resources to handle these problems, I fear that things like this will happen in my hometown, and that is unacceptable."
It turned out Johnson was not the rape suspect sought by police, which Narcisse said only underscores the senselessness of Cotton's death.
"This is a somber but a very sobering occasion for us," he said. "It brings us back to the reality of police work. It's incredibly saddening considering the senselessness of the crime." E-mail to a friend