HOUSTON, Texas (KTRK) -- A 20-year-old man arrested and charged in the armed robbery of a couple outside their west Houston home is accused of fatally shooting a man in southwest Houston on the same day.
Michael Coates was arrested for aggravated robbery on Wednesday, March 22 -- two days after Houston police said they were looking for him and released his mugshot.
Two days after his arrest, on Friday, March 25, Coates was charged with murder in the shooting death of 29-year-old Marcus Mercado.
Mercado's family said he was a father of two and wanted to know why someone would do this to him.
"He would just show up, and he would brighten your whole day," Mercado's mother, Christie Flowers, said. "I don't know who the man was, and I know for sure my son didn't either."
Investigators with the Houston Police Department said both crimes occurred on Feb. 11. Surveillance video shows the suspect during both incidents.
The aggravated robbery happened in the 10200 block of Briar Forest Drive.
READ MORE: Video shows woman scream as armed robber holds her up in her own garage in Briar Forest area
Police said a 75-year-old woman was loading a box into her car, which was parked inside her garage when a man ran up to her from behind with a gun. The robber was demanding her car keys, HPD said.
In the surveillance video, you can hear the woman scream as the robber makes his demands.
Police said the woman's 77-year-old husband heard her scream and opened the front door to see what had happened.
That's when the robber pointed the gun at the husband instead. The suspect demanded the car keys and briefly followed the husband into the house, HPD said.
The suspect took the keys to the couple's black, four-door BMW sedan and drove off, according to police.
Investigators found the BMW unoccupied the next day on a residential street near an apartment complex at 5401 Rampart Street.
Coates was identified as the suspect in the case thanks to the surveillance video and a tip sent to Crime Stoppers, according to court documents.
On the same day, HPD responded to a shots fired call just before 12:30 p.m. at a convenience store at 9834 Meadowglen Lane. At the scene, officers found a man dead with gunshot wounds.
The victim was later identified as Mercado.
Investigators said it appeared there was some sort of altercation between the suspect and Mercado, and that's when the suspect drew a pistol, shot the victim multiple times, and fled on foot.
Surveillance video from a nearby business showed the moment the suspect, later identified by police as Coates, pulled out the pistol and aimed it at Mercado.
Coates was scheduled to appear in court on Monday for the murder charge. It's now scheduled for Tuesday at 9 a.m. His next court date for the aggravated robbery charge is scheduled for May 4.
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