OLATHE, Kan. — A 17-year-old pleaded not guilty to first-degree murder at the same time he should be beginning another year in a metro high school.

The teenager is one of seven teens charged in the May homicide of 19-year-old Marco Cardino, of Smithville, Missouri.

Prosecutors have asked to certify the teenager as an adult, but a judge has not ruled on the request. Since the teenager’s case remains in juvenile court at this point, FOX4 is not reporting the suspect’s name.

Court documents allege the teenager was among a group who plotted to intentionally kill Cardino during a drug deal at Black Bob Park.

A court filing by a lawyer for one of the teenagers shows the suspects took masks and a gun with them when they went to the park to buy drugs from Cardino. The document also shows one of the teenagers told investigators she believed the other teenagers planned ahead to steal the marijuana Cardino showed up to sell them.

Police arrested the seventh teenager earlier this month. He is currently in custody, and the judge approved a request for the teenager to undergo a mental health evaluation before his next hearing.

The teenager is scheduled to return to court next month.

One of the other teenagers charged in the case already pleaded guilty to second-degree intentional murder in Cardino’s death.

As part of a plea deal, 14-year-old Kristofor Washington will serve up to eight years in a juvenile facility, but has the possibility of being released earlier for good behavior.

Washington’s sentencing is scheduled to take place Aug. 24.

The other five teenagers charged in the homicide have pleaded not guilty to first-degree murder charges.

Prosecutors have requested to certify the other three 14-year-olds as adults. Kansas law does not allow the two 13-year-olds charged in the case to be tried as adults.