WASHINGTON (WUSA9) — A DC man with a lengthy criminal history eluded authorities after a technician incorrectly placed a GPS tracking device on his prosthetic leg.

“I’m just so hurt and I just hope I can deal with it,” said the victim’s mother, Lillie Hamilton. “It’s just really getting to me.”

The 34-year-old suspect, Quincy Green, appeared to be at his South Capitol Street apartment when he allegedly gunned down an Oxon Hill man in May.

According to the Director of Pre-Trial Services at DC Superior Court, “It was human error. Plain and simple.” Now the blame has shifted to the California-based government contractor who incorrectly installed the device.

“This is the worst that’s really happened to me all my life and I’m 72 years old,” Hamilton said.

Her only son, Dana, was murdered on May 14 on a Southern Avenue sidewalk in Southeast DC. He was 44 years old and lived with his mother.

After a gun possession charge in April, Dana Hamilton’s alleged killer was confined to his home while awaiting trial. He was equipped with a GPS tracking device. But somehow, the technician from Sentinel, the California-based government contractor, placed it on Green’s prosthetic leg.

“Here you have a company [Sentinel] that comes along and working with DC government, doesn’t even follow their own protocols,” said Russ Mullins, an Executive Shop Steward at the Fraternal Order of Police.

Charging documents reveal Green simply removed his prosthetic leg and used a spare, allowing him to leave his apartment at his own will.

“Why would they put it on a prosthetic leg?!” Dana’s mother said. “When it was supposed to go on the person’s real leg?”

This unprecedented incident has frustrated law enforcement too.

“Not putting the device skin to device like they’re supposed to, now we have this young man that goes out and eventually kills someone. What do you say to the family?” Mullins said.

At any given time, DC monitors about 400 offenders. WUSA9 was told thousands of tracking devices have been installed by this company, but never with an outcome like this.

Sentinel had not responded to WUSA9’s requests for comment. WUSA9 wants to find out whether the employee who incorrectly installed the device will be disciplined or terminated.