PHILADEPHIA (AP) — An unrepaired fence, switched-off motion sensors and a sleeping guard are among the factors that helped two men escape from a city prison earlier this year and led to their absence being unnoticed for 19 hours, Philadelphia’s prosecutor said Wednesday.

Ameen Hurst, now 19, and Nasir Grant, 24, escaped from the Philadelphia Industrial Correction Center in northeast Philadelphia on May 7. Hurst, who had been charged with four counts of murder, was arrested after 10 days. Grant, held on conspiracy drug and weapons charges, was taken into custody four days after the escape.

The two escaped through a gap cut in the fence that had been there for nearly seven weeks and had been noticed by prison staffers at least four days before the escape, District Attorney Larry Krasner told members of the Philadelphia City Council, The Philadelphia Inquirer reported.

Krasner played video showing the inmates opening cell doors that were supposed to be locked with inmates inside for the night, then showed them walking down a hallway and crawling toward a door as another prisoner — also out of his cell — acted as a lookout, the newspaper said.

One guard post in the cellblock was unoccupied and another guard monitoring the unit also had to watch two other areas, Krasner said. Another guard later reported for duty but fell asleep, then didn’t conduct required prisoner counts, which allowed the long delay in detecting the escape, Krasner said. Also, a motion detection system plagued by many false alarms due to geese landing in the area had been “turned off for more than a decade,” he said.

Commissioner Blanche Carney of the city prisons department cited a staffing shortage in the aftermath of the coronavirus pandemic as a major problem. She said changes in executive leadership had been made and she had asked state prison officials for a security assessment. Carney also said the jails had installed additional razor wire and hoped to upgrade video systems and install new technology such as armbands offering real-time location on those incarcerated, the Inquirer said.

Four people have been charged with helping the escapees. Krasner didn’t announce any new arrests on Wednesday but said the investigation was ongoing, and that he would present council members with more details in private.