BANGOR, Maine — A former student who was assaulted at the Job Corps center in Limestone and his mother have sued the company that operates the school over the student’s dismissal last year.

Gregory Poindexter and Chevonne Handy of Stamford, Conn., allege that Poindexter was assaulted by three other students when he was 17, then kicked out of school because of alleged gang activity.

Because Poindexter was underage when the incident happened, his mother is a plaintiff in the lawsuit.

Portland attorney James Clifford filed the lawsuit April 13 against Career Systems Development Corp. and U.S. Secretary of Labor Hilda L. Solis in U.S. District Court in Bangor. The U.S. Department of Labor is the federal agency charged with oversight of the Job Corps program.

The lawsuit has not been served on Career Systems, according to the court docket.

“I can’t comment on something I haven’t seen,” Jeff Stinson, senior vice president of human resources for the firm, located in Irvine, Calif., said Tuesday.

Poindexter and his mother are seeking his reinstatement into the Job Corps program along with unspecified compensatory and punitive damages.

The complaint alleges that Poindexter was denied due process during the dismissal proceeding and was discriminated against on the basis of race. The lawsuit also charges that Career Systems Development Corp. was negligent in caring for Poindexter after the assault, in which his jaw was broken, and in its oversight of students at the Loring Job Corps Center.

Poindexter, now 19, was studying welding when he was a student at school in Limestone.

He was attacked on Dec. 5, 2010, according to the complaint. He was granted medical leave the next day. A senior staff member from the Loring center accompanied him from Presque Isle to Boston, directed him to the gate for his connecting flight, then left the airport.

His connecting flight to White Plains, N.Y., was canceled because of a snowstorm and his mother could not reach him because Career Systems’ staff had taken his cell phone, the complaint said. Airline staff noticed he was a minor and traveling alone. He arrived home on Dec. 7.

On Dec. 8, Handy was told her son had been dismissed after a hearing held that day before the Behavior Review Board. Neither Handy nor her son was informed of the hearing, according to the complaint.

“CSD stated that the three-member board unanimously found Mr. Poindexter had engaged in ‘gang activity including wearing of gang clothing, colors, or making signs or handshakes that are associated with known gangs’ and ‘inciting disturbance and creating disorder,’” the complaint said.

Clifford denied Tuesday that Poindexter was involved in any type of gang activity.

The attorney appealed the board’s decision. It was denied on Feb. 1, 2011, according to the complaint.

Assault charges were filed in connection with the assault on Poindexter against two former students at the Loring Job Corps Center in Caribou District Court, according to Clifford.

Franklin Leonard, 19, of Limestone was convicted of Class D assault in March 2011 after a trial, John Pluto, assistant district attorney for Aroostook County, said Tuesday. Leonard was sentenced to 90 days in jail with all but six days suspended and ordered to pay a $500 fine.

Poindexter testified against Leonard, according to the complaint.

A second student was charged but not convicted, the prosecutor said.

Leonard faced up to a year in prison and a fine of up to $2,000.