Cpl. Trevor Parham, 40, turned himself in on Thursday morning on charges of simple assault and official oppression. He is now free on $25,000 bail.
"This is unfortunate, it's disappointing and it's offensive," said Delaware County District Attorney John Whelan.
Parham is accused of using a Taser on 17-year-old Da'Qwaun Jackson. At the time, Jackson was handcuffed and shackled in a holding cell back in late April.
Investigators say Parham sent a text message to a fellow officer saying he had "locked up a kid" and he "got Tased in the cell LOL."
Investigators say Parham admitted to using the Taser on the boy while he was in the cell. Still, Parham's lawyer, Thomas Fitzpatrick, said he will be cleared of these charges.
"These accusations have disheartened him, certainly, but he is someone who has a rather spotless record as it pertains to any accusation of excessive force in his law enforcement career," Fitzpatrick said.
Jackson declined to be interviewed on Thursday, but says he's glad Parham has been charged and he hopes he never wears the badge again.
The incident created an uproar in Colwyn and threw the police department into turmoil. The mayor twice declared a state of emergency.
Other officers, including the acting chief, remain under investigation for allegedly trying to cover up the incident.
"The actions of the borough officials, including the police officers surrounding this particular incident are under review," said Whelan.
The D.A. says the investigation should be wrapped up in a few weeks, saying his office will follow the evidence wherever it leads.