MESA, Ariz. -- A suburban Phoenix police chief says he's asked an outside group to review his department's use-of-force incidents after a second controversial arrest seen on video, this time of a 15-year-old boy. Mesa Police said two officers are now on administrative leave while they investigate a use of force that occurred on May 17 during the arrest of a teen armed robbery suspect, reports CBS affiliate KPHO.

This new incident comes just days after a man claims he was a victim of police brutality at a Mesa apartment complex. Surveillance and bodycam video show the man getting hit and kicked by police officers while they detain him. Four officers in that case were also placed on administrative leave.

A teen's May 17 arrest has promoted a use-of-force investigation by the Mesa Police Department Mesa Police Department

On Friday, Mesa Police Chief Ramon Batista announced at a press conference that he had asked the nonprofit Police Executive Research Forum to conduct a "comprehensive and full investigation into the department's use of force events over the past three years, as well as policies procedures and training."

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Batista also announced that former Maricopa County Attorney Rick Romley had agreed to conduct a separate investigation and to report his findings directly to the chief.

"The events seen this week are unacceptable for a police department with our grand stature," Batista said in a tweet Friday. "We are at a critical time in the organization. We have lost our way in this arena. You deserve our best!"

In the latest incident, body-camera video from one officer shows him running up to the boy and a 16-year-old girl lying on the ground with their hands spread. Officers can be heard shouting with their guns drawn. They put the teens in handcuffs and the boy can be heard swearing at the police officers. He then screams out like he's in pain.

The police officers are looking for the gun that they said they saw him with at a nearby convenience store. He said he didn't have a gun.

"I'm just trying to get home!" the teen said.

Police search him for the weapon but don't find anything.

"Where's the gun?" one of the officers said.

"No gun!" the teen replies, seemingly in pain.

Police tell him to sit and stop moving.

"I'm sorry I'm not going to try to arm wrestle with you guys," the boy said.

KPHO reports that in the police report, officers said the teenagers were taken into custody without incident.

According to KPHO, police say the situation began when the boy, who was with the girl, got into a verbal fight at a convenience store with a man he knew and started waving a sawed-off shotgun or rifle around at customers at the store. Police said that the teens went into the man's car outside the store and that the boy busted out the windshield with the gun, before they both ran off.

KPHO reports that officers said they spotted the pair at an apartment complex and the two initially ran from police. Police said they found a backpack belonging to the pair where they were initially spotted and inside was a sawed-off shotgun or rifle.

The boy and the girl were arrested and charged with multiple counts including armed robbery, aggravated robbery, aggravated assault with a deadly weapon, theft of means of transportation, a minor illegally possessing firearms and criminal damage.

After police reviewed the body-worn camera footage, two officers were placed on leave, the department said.