Nearly every Fort Worth police officer has probably heard the radio call.
"Sansom Park's chasing one."
A black Dodge truck was racing west on Jacksboro Highway. Somebody had driven away from Dean's Food Mart without paying.
A highway chase is nothing unusual.
Nobody would automatically think that the chase might lead to the shooting of a Fort Worth police officer days later.
That's the point. Nobody ever knows who's behind the wheel in a police chase, or why he's running.
Or what some fugitive ex-con might do two days later if an officer delivers an arrest warrant to the door.
The shooting of officer Henry "Hank" Nava brought a chill to police families across North Texas on Wednesday.
"We might have been shot at, too," Sansom Park police Capt. J. Boone said.
"If somebody runs, they're not running over a few dollars worth of gas. There's a reason."
What's also unusual is that the man facing an attempted capital murder charge had a mostly nonviolent criminal record.
Bedford Police Chief David Flory, director of training for the Texas Tactical Police Officers Association, listened as I read off Stephen Lance Heard's police record: forgeries, a drug case, something involving a car that wasn't his, and a 1994 assault in Dallas.
"They probably didn't expect this kind of violence," Flory said.
"It happens every day. You think you're dealing with somebody who's low-risk. They fight you. They resist arrest. They turn out to be armed."
Knocking on a door might be the least predictable moment in police work. An officer might find nobody home. Or the occupants might open fire.
"That's what makes police work so dangerous," Flory said. "You never know what you're dealing with."
In 1933, a Tarrant County sheriff's deputy went to a door in Dallas looking for a bank robber.
Deputy Malcolm Davis of Grapevine was shot dead by outlaw Clyde Barrow.
In 1978, Fort Worth police officer Jimmie Chadwell was shot and killed serving a warrant at a home on Ellis Avenue on the north side.
A man inside shot Chadwell.
It was two weeks before Christmas.
Like Nava, Chadwell was a father. Nava has a daughter, 9, and a son, 4. Chadwell had a son who was 9.
Chadwell's 9-year-old is now the principal at Northwest High School.
"Not a day goes by that I don't think about my father," said Jim Chadwell, 36.
He was at a conference in North Carolina on Tuesday. Somebody mentioned that an officer had been shot.
When his plane landed Wednesday, Chadwell went straight to the airport newsstand for a paper.
"When you think of police with a warrant, you think of glamorized TV shows where they have it surrounded with all kinds of support," he said. "But typically, you don't have that. You wouldn't always expect someone to draw a weapon."
His father was killed while serving a misdemeanor warrant. He was also wounded by police returning fire.
"All you know is that somebody might be inside that house, and there's a warrant out for their arrest," Chadwell said. "You have no idea what might happen."
He's still close to the police.
He proudly keeps his father's badge in his office at the high school in far north Fort Worth.
"They put their lives on the line every day," he said. "They never have any idea whether the next person they see will try to harm them."
Instead of patrolling, he has spent his career as a coach and teacher.
I asked him what he would tell Nava's children.
"The same thing I would tell anybody," he said.
"There is *nothing* easy about being the child of a police officer.