FRESNO — FRESNO -- Lawrence Jones, the gunman who opened fire at Valley Protein, was depicted by police Wednesday as a deeply disturbed loner who fancied himself a rap music gangster or an African head of state in letters he wrote to women he watched on Spanish-language television.

In a news conference, Fresno Police Chief Jerry Dyer chronicled Jones' killing trek through the central Fresno meat processing plant Nov. 6 and described the traumatic aftermath facing survivors.

Dyer said that what sparked the slaughter is still unknown. But a co-worker who served time in prison told police that Jones, who did time for robbery and other crimes, acted as if he was still behind bars in his mannerisms, kept to himself and inexplicably walked away from work assignments.

Jones, 42, fatally shot Salvador Diaz, 32, and Manuel Verdin, 34, critically wounded Arnulfo Conrriquez, 28, and less seriously injured Fatima Lopez, 32, before taking his own life.

Police gained some insight into Jones through a 2004 psychologist's report that diagnosed him as having an intermittent explosive disorder and multiple substance abuse.

They learned more about him when they searched his apartment and found 23 letters he wrote -- but never sent -- that showed he was "infatuated" with rap music and women he found attractive, Dyer said.

Some of the women Jones came across in everyday life. Others he spotted on shows featuring attractive women in racy outfits on Univision, the Spanish-language television network.

In the letters he wrote to those women, Jones would channel now dead Oakland drug dealer Felix Mitchell or the president of Nigeria.

"I am inspired to introduce myself to you," the letters began.

Detectives have confirmed that the murder weapon was stolen.

The serial numbers were filed off the .357 Magnum four-shot derringer, but technicians at the federal Bureau of Alcohol, Tobacco and Firearms managed to restore the digits.

It was stolen June 8 in a burglary on the 5500 block of East Grant Avenue, a county island south of Belmont Avenue and west of Clovis Avenue.

There were 62 workers in Valley Protein when the shooting began, and 22 of them witnessed the violence.

Dyer said police chaplains have counseled many of the co-workers and described the sessions as "very emotional," with some breaking down while trying to cope with the events.