ST. PETERSBURG, Fla. (AP) - City police officers are mourning their third colleague slain in the line of duty in 30 days, but they have been forced to put their emotions on hold as they work overtime to search for the suspected killer.

Officer David Crawford was shot Monday night investigating a report of a suspicious person in a neighborhood just south of Tropicana Field - where the Tampa Bay Rays play baseball.

"You have a job to do, you're a professional," said St. Petersburg Detective Mark Marland. "You kind of have to push a little bit of the somberness and the heavy heart to the back."

So far, there are few leads. The suspect left behind his Nike flip-flops and witnesses gave detectives a vague description of a young man wearing dark shorts and white socks. Officers at the department of about 540 people were are working 12-hour shifts to help the investigation.

"We're torn between grieving and our jobs and the mission," said St. Petersburg Police Chief Chuck Harmon. "But everybody is committed to the mission at this point."

Officials said the shooting happened after two officers were called to investigate a report of a prowler.

Crawford, 46, spotted a suspect and got out of his vehicle. At 10:37 p.m., another officer, Donald J. Ziglar, reported an exchange of gunfire and told dispatchers an officer was down.

Ziglar found Crawford lying on the pavement near his cruiser, police said. He had been shot multiple times at close range. Officials said Crawford was not wearing a bullet proof vest.

Helicopters, SWAT teams, dozens of law enforcement and dogs searched for the gunman. There was no evidence that the suspect was
injured during the gunfire exchange, Chief Harmon said.

An entire swath of the city was inaccessible to traffic; Harmon said the department will keep the perimeter "until we knock on every door."

The FBI, the St. Petersburg Police and other groups also were offering a reward of $100,000 for information leading to the identification and arrest of the suspect.

Crawford, who was married, eligible for retirement and the father of an adult daughter, was pronounced dead at a hospital. Officers saluted the van that carried his body to the medical examiner's office Tuesday morning.

On Jan. 24, two St. Petersburg officers - Jeffrey A. Yaslowitz and Thomas Baitinger - were killed as they helped serve a warrant on a man with a long criminal history. Prior to that, the St. Petersburg Police department hadn't had an officer killed in the line of duty in more than 30 years.

"We're not even done healing from the first tragedy, then boom, we have a second one," said Marland, who is also the St. Petersburg police union president.

Lorie Fridell, an associate professor of criminology at the University of South Florida in Tampa, said such tragedies reinforce the resolve of the officers.

"I don't think that there are many officers that are rethinking their careers," said Fridell. "They understand the danger. If anything, tragedies like this strengthen their commitment, particularly the commitment they have for fellow officers.

"I expect that particularly right now, officers are ever vigilant, maybe even increasingly vigilant, in the Tampa-St. Pete area as a result of these tragedies."

Maki Haberfeld, chair of the Department of Law & Police Science at John Jay College in New York, said she suspects officers in St. Petersburg will be more anxious in the coming months.

"Certainly there is always a level of preparedness that the police officers have to be ready for," said Haberfield. "Of course now they will be more on guard. The issue is whether or not they are going to be more willing to use force, lethal force."

Crisis counselors have been called to help officers in the department.

"Officers unfortunately don't get downtime to show their emotions," said Michael Krohn, the executive director of the Suncoast Police Benevolent Association, the union that represents St. Petersburg officers. "They have to get the job done and be safe. The time to break down is after the shift, at home."