HOUSTON -- A robber and a clerk died Friday in shootings at two separate convenience stores in the Houston area, KPRC Local 2 reported.

The latest shooting happened at the Tony's Express Store in the 4000 block of Synott in southwest Houston.

Investigators said just before 3 a.m., a store clerk shot two robbers who were stealing money from the register.

The robbers ran out of the store, drove around the corner in a pickup truck, and then crashed into the cab of a parked 18-wheeler, police said. The driver of the pickup died behind the wheel.

"At that point, the passenger jumped from the truck and fled the scene, ran down the street to another apartment. He was later apprehended and he is currently at Ben Taub Hospital with unknown injuries," Houston Police detective Roger Chappell told KPRC Local 2.

Four hours earlier, police said there was another fatal shooting at the K.K. Food Store at 6650 Bellfort in southeast Houston.

The store clerk was killed.

Investigators said just before 11 p.m. Thursday, two customers walked in and found the 23-year-old clerk on the ground.

Paramedics rushed him to the hospital, but he was already dead from a gunshot wound to the neck.

"It appears that he was shot and that robbery was the motive," Houston Police detective E.R. Carstens said.

The victim's name was not released.

Experienced store clerks said protection is the key.

"Everybody, you look at. This is bulletproof because people shoot," an unidentified clerk said.

Police said they have no suspects in the second case and are asking anybody with information to call Crime Stoppers at 713-222-TIPS.

Investigators said the cases do not appear to be connected and are separate incidents.