A Michigan, U.S., teen Tanaya Lewis could spend up to life behind bars if convicted for fatally stabbing a classmate Danyna Gibson to death and at the same time “smiling and laughing” during the attack.

Lewis, 17, was charged with first-degree murder Friday for stabbing Gibson once in the chest striking her heart and then in the back with a kitchen-style steak knife.

Under state law, all 17-year-olds are charged as adults if arrested for any offense.

Two dozen students watched in horror as Lewis killed Gibson, 16, with a kitchen knife in a classroom Wednesday at Fitzgerald High School in Warren, Michigan, U.S., Fox 2 Detroit reports.

“Witnesses said the defendant was smiling and laughing as she was chasing the victim,” Detective Donald Seidel of the Warren Police Department told a judge Friday, as WXYZ-TV reported Saturday.

One blow penetrated Danyna’s heart, the station reported.

Prosecutors said Lewis screamed, “I’m going to kill her” as a teacher tried to shove her out of the classroom, according to the station.

Police said there was animosity between the two straight-A students over a boy.

Lewis is being held without bail on a capital murder charge.

She said “yes” to the judge when asked if she understood that she is facing life behind bars without parole.

Danyna’s family is soliciting funds on GoFundMe for her funeral.

Meanwhile, funeral arrangements were set Saturday for 16-year-old Gibson, who finally died at St. John Macomb-Oakland Hospital in Madison Heights after the stabbing, inside their second-period economics class.

Visitation for Gibson is Tuesday from 11 a.m. to 9 p.m. at the Hutchison Funeral Home, at 6051 East Seven Mile in Detroit.

Her funeral is Wednesday at New St. Paul Missionary Church, at 21050 Ascension Avenue in Warren.

Family hour is at 10:30 a.m. and the funeral service is 11 a.m., according to the funeral home.

Gibson was involved in the National Honor Society, the school’s cross country team, student council, robotics club, color guard and marching band. (NAN)