The suspect in an Oct. 5 shooting that injured 11 people on Massachusetts Street pleaded guilty to all charges against him Friday, but prosecutors weren’t exactly satisfied with the outcome.

Jason A. Tremble, 21, pleaded guilty to a 13-count complaint, including charges of aggravated battery and being a felon in possession of a firearm.

“I discharged a firearm in the ground, and it hit unexpected people that it wasn’t supposed to hit,” Tremble told Judge Paula Martin.

Tremble’s plea, however, was a surprise to prosecutors. It came as Assistant Dist. Atty. Dave Zabel was preparing to upgrade the severity of the charges in relation to two of the shooting victims.

Zabel wanted to change two of the aggravated battery charges from level 8 felonies to more severe level 5 felonies, arguing that the two victims had suffered “great bodily harm,” the damage required to prove the more serious charge. Prosecutors wouldn’t discuss the nature of the injuries.

But Judge Paula Martin said she couldn’t legally allow the charges to be changed because Tremble already had waived his right to a preliminary hearing and was prepared to enter a guilty plea.

“I am dutybound to accept this plea,” Martin said.

Zabel even considered dismissing the charges, so that the state could then refile the more serious aggravated battery charges against the defendant, though that move would have resulted in Tremble being released from jail. But Martin said she would not allow the state to withdraw the charges either.

For someone with Tremble’s criminal background, being convicted of a level 8 felony means a presumed sentence of about 19 months in prison, compared with 120 months for a level 5 felony.

¢ 6News video: Gunman pleads guilty¢ Suspect in shooting was on probation (10-8-03)¢ 6News video: Shooting suspect was on probation¢ Suspect charged in shooting (10-7-03)¢ 6News video: Shooting suspect charged with aggravated battery (10-7-03)¢ Shooting outside bar injures 11 (10-6-03)

Dist. Atty. Christine Kenney said the more severe charges could have changed the outcome of the case significantly by sending Tremble to prison nearly 10 years longer than the charges to which he pleaded guilty.

The District Attorney’s Office is now considering whether to appeal Martin’s decision.

“We believe we should have been allowed to file an amended complaint,” Kenney said.

Tremble admitted committing a kind of crime that police said had never happened in Lawrence: firing indiscriminately into a crowd of late-night bar patrons.

Many of the victims and their parents filled the courtroom for Friday’s proceedings.

Police said Tremble was trying to skip bullets off the pavement and into the crowd during the early-morning shooting Oct. 5 outside It’s Brothers Bar & Grill, 1105 Mass.

Tremble was on probation in Shawnee County at the time of the shooting, even though, according to the state’s sentencing guidelines, he could have been sent to prison for 34 months after pleading no contest in Topeka to possession of narcotics and obstruction of justice.

Martin set Tremble’s sentencing for Dec. 18.