A former St. Paul police officer on trial for assault was working in a home for troubled youth when he punched a teenager with a left hook and “dropped him to the ground,” before continuing the attack, a prosecutor asserted during opening statements Wednesday.

Assistant Ramsey County Attorney Cory Tennison told jurors that Clemmie H. Tucker Sr. inflicted “very, very significant” bruising on a then-14-year-old boy with mental health issues at the Vintage Youth group home last year.

Tucker’s trial in Ramsey County District Court started Wednesday with opening statements and testimony. He is charged with one count of malicious punishment of a child for the Jan. 30 assault.

Tucker retired from the department as a sergeant in the 1990s after 23 years. In 2006, he pleaded guilty in federal court to possessing about 22 pounds of cocaine and 8 pounds of methamphetamine estimated to be worth $4 million.

Tucker’s attorney, Christopher Zipko, told jurors that surveillance video Tennison is expected to present at trial will omit important details. The boy had assaulted another resident, giving the resident a bloody lip and chipped tooth, before he got “into” Tucker’s face, Zipko said.

“What you’re going to get is a story that absolutely doesn’t congeal,” Zipko said. “These are male juveniles who are aggressive.”

Tennison said that Tucker grew angry and assaulted the boy after the boy got into an argument with another resident over a video game controller and then “stood up” to Tucker. At least one resident witnessed the assault, and will testify that the boy did not raise a hand at Tucker, Tennison said.

Tennison told jurors he allegedly asked the witness, “ ‘You want some, too?’ ”

Tucker tried to interfere and talk over the 14-year-old boy as police were questioning him, the prosecutor said.

Zipko painted a picture of a troubled group home where staff were instructed to refrain from calling police. The facility had a conditional license at the time due to a number of problems they had with the state, he said. “This did not happen in a vacuum,” Zipko said. “This did not happen because [the teen] has some afflictions.”

Laura Urtel, a children’s mental health manager who works with the boy, testified that he is on the autism spectrum and has several mental health issues, including attention deficit hyperactivity disorder, disruptive mood disorder and outbursts of aggression and foul language caused by prenatal exposure to alcohol.

Urtel testified that she told the staff at Vintage Place the boy needed extra care and supervision because of his issues, and because other residents had “targeted” and assaulted him. “They struggled a little bit,” Urtel said of the home’s efforts with the boy.

The state revoked Vintage Place’s license last October due to a number of violations.

Chao Xiong • 612-270-4708

Twitter: @ChaoStrib