‘Thrill Killer’ Suspected in Six Murders : Crime: Three employees of a pizza parlor in a Sacramento suburb are the latest victims. Three people were slain a week earlier at a store a mile away.

Authorities believe a “thrill killer” is behind two shootings within a week that have left six people dead.

Sheriff’s officials advised late-night stores and restaurants in northeastern Sacramento suburbs to take extra security precautions Wednesday, a day after three employees of a pizza parlor were fatally wounded in the head.

Investigators said the victims were killed with the same handgun used to murder two employees and a customer a week earlier at a convenience store a mile away.

“From our experience with these crimes, we really feel we’re probably dealing with an individual who has a psychological motive. . . . This individual likes to kill,” Lt. Ray Biondi, head of the sheriff’s homicide division, told reporters.

“We’re going on the assumption that he’ll kill again,” Biondi added, calling the gunman a thrill killer.

Investigators had no witnesses and few leads in the shootings. Sheriff Glen Craig assigned more than 85 detectives to contact all businesses open Wednesday night. Craig said deputies would also question parolees and people wanted on arrest warrants for information. He appealed to the public to report anything suspicious.

The pizzeria shootings were discovered about 11 p.m. Tuesday when employees of a Round Table Pizza called another Round Table pizzeria and did not get an answer. They went to the restaurant and found the three employees lying in a rear kitchen area.

Sarah Crook, 18, of Carmichael and Kyle Reynolds, 19, of Sacramento were dead. Both were students at American River College.

The third victim, Andrea Coladangelo, 30, of Sacramento, died at University Medical Center.

All three were shot in the head at close range, officials said. Tests on shell casings found in the restaurant determined that they were from the same handgun used in the earlier shootings, officials said.

While money was stolen from both businesses, Biondi believes “the robberies were, more or less, a cover-up for the actual killings.”

Authorities disclosed few details about the shootings, saying that could jeopardize their investigation. However, they noted that both crimes occurred about the same time of night on a Tuesday and that the weapon and method of killing appeared to be the same.

On Feb. 12, a customer discovered two employees dead behind the counter of the Quik Stop Market and a mortally wounded customer in front of the store. They were identified as employees Zeid Ahmad Obeid, 20, and Stephen Anderson, 35, and customer Thor Johnson Sr., 42.

Biondi said the killer probably lives or works in the area. While the gunman probably was a stranger to the victims, he may hold grudges against the businesses, or “he may just enjoy killing,” the lieutenant added.