Guns and senility don’t mix well.

LUBBOCK, TX (KCBD) -

A 911 call is shedding new light on a frightening evening for a Lubbock man and his 6-year-old son.

Police say 80-year-old Robert Miller held Brandon Stacker at gunpoint in the alley behind his house. It happened on 17th Street near Chicago Avenue Monday night.

Stacker told 911, “He’s standing right here with the gun in my face.”

Stacker tells us he was in the alley with his 6-year-old son Monday night when Miller and his dog came out of his gate.

“He said ‘what are you doing dumping trash in my dumpster?’ From there he said he was armed,” Stacker said.

Stacker asked Miller to call his dog back because he was worried about his son. Stacker says Miller refused and displayed a shotgun.

“He pointed the gun at my son and he’s threatened serious bodily injury to both of us,” Stacker said.

Stacker says they had been cleaning up his house one street over and drove to the alley to discard the trash in the dumpster. According to Stacker, Miller said he didn’t want his dumpster being used.

Stacker told his 6-year-old to get in the car and called 911.

He was on the phone with dispatch for nearly 20 minutes before police arrived. Stacker says Miller had the shotgun pointed at him for the entire time.

Dispatch: “Police are on their way.” Stacker: “I sure hope so, because this could end badly.”

Roger’s wife Lavora Miller also called 911, concerned about the strangers out behind her house.

Lavora Miller told dispatchers, “They have a vehicle with the trailer and he’s on the phone. I don’t know if they’re dumpster diving, I don’t know what’s going on.”

Police arrested Robert Miller and charged him with aggravated assault. He has since bonded out.

More: 911 AUDIO: Father & Son Held at Gunpoint by 80-Year-Old Man - KCBD NewsChannel 11 Lubbock