A detention officer with the Maricopa County Sheriff's Office in Arizona died Thursday after being shot in the driveway of his Arizona home while he prepared to head to work, police said.
The attack occurred about 4 a.m. The worker was rushed to a hospital but died a short time later, Phoenix police Sgt. Trent Crump said.
No one was in custody and there was no information on a motive, he said.
"It's really a whodunit," Crump said.
The employee's name was not released. The Sheriff's Office declined comment until a news conference set for Thursday afternoon.
Crump said the employee was a jail detention officer, and investigators were looking into whether the shooting was connected to his job.
A man was seen running from the scene after neighbors heard shots and found the critically wounded man in his driveway.
Police set up a perimeter around several blocks near the home before lifting it about two hours later after a police dog and tactical teams conducted a search.
Crump said several people have been questioned.
The shooting occurred in a Phoenix neighborhood that uses a Tolleson address.