Mount Vernon police say a prisoner is in the hospital after he was shot in the leg by another inmate while they were inside of a prisoner transport van Thursday night.

"It's messed up. They're supposed to be searched before they go into lock up," resident Leroy Sewell says.

Police say the shooting happened near West Lincoln Avenue and Oak Street in Mount Vernon as five prisoners were being taken to Westchester County Jail.

Chief Marcel Olifiers says two Mount Vernon officers were in the front seat of the van when the gun went off.

"The officers reported hearing a single gunshot from the rear of the van followed by a prisoner stating that he had been shot," Olifiers says.

The chief says the officers immediately returned to police headquarters.

The prisoners were removed from the van, and a firearm was recovered from one of them.

"The weapon had one spent round and four live rounds remaining. The firearm has not been reported stolen and full firearm trace is underway," Olifiers says.

Police identify the alleged shooter as Louis Soto, 32, of the Bronx.

They say he was arrested on Oct. 15 and was being taken to county jail on a Forcible Touching charge.

He's now facing additional charges.

"The firearm should have been detected prior to the transport. Effective immediately, use of the department's magnetometer and handheld wand is now mandatory for all new prisoner processing," Olifiers says.

However, community members say they have even more questions for the officers who were in charge of the transport.

"How could that have happened? They were in custody. So, somebody was sleeping on their job," one woman says.

Police say some of the officers involved have been assigned to desk duty while the investigation continues.

Officials also say they're going to do a review of the department's policies and procedures.

The Law Enforcement Integrity Bureau within the district attorney's office is also conducting an independent review of the incident.