"I am angry, sickened, dismayed, saddened by the allegations and charges. We have worked very hard to improve and uplift the professionalism of the Lawrence Police Department," Rivera said.

"We have fired and forced out many officers who did not meet and could not stand up to the code of conduct and the high level of professionalism that my office, the chief of police and the men and women and leadership of the police unions have worked to establish."

"If found to be true we will move swiftly to remove the officer involved," Rivera said. "This is a travesty."

Vieira, who has been a Lawrence police officer since November 1999, was placed on administrative leave "immediately after the department was notified of his arrest by the Massachusetts State Police," Lawrence Police Chief Roy Vasque said in a statement.

"This is an ongoing investigation, but the allegations against Officer Vieira are extremely troubling, and we take them very seriously," Vasque said.

Authorities began investigating in January when the victim's mother contacted the DA reporting that her 13-year-old son allegedly met Vieira using a social media app. She says Vieira allegedly engaged in sexual activity with him in the summer of 2018.

Vieira is scheduled for arraignment on Tuesday in Lawrence District Court.