A St. Tammany Parish woman has been sentenced to 40 years in prison on a reduced charge after agreeing to testify against her two alleged accomplices in a Slidell murder.

Katelyn Marie Lusich, 20, pleaded guilty Sept. 5 to obstruction of justice as part of the deal with prosecutors.

She is expected to serve about 13 years, according to her attorney, Rachel Yazbeck.

Lusich still faces counts of second-degree murder and aggravated arson, but those counts will be dropped once she testifies against Andrew Sumner, her former boyfriend, and Devin Baham, a second alleged accomplice, Yazbeck said.

According to police, Lusich drove the two men to Ashley King’s Bayou Lane apartment so they could rob her of drugs and money in February 2012. While Lusich waited in the car, Sumner and Baham went inside, with Sumner returning a little while later to say King had been stabbed to death when the robbery went awry. The three left, but the two men returned later and set fire to the apartment, police said.

Just a day later, Slidell police arrested the trio.

Lusich’s plea ended a somewhat winding legal road for her case. After she was first arrested, prosecutors charged her with being an accessory after the fact to first-degree murder and armed robbery. But in May 2013, prosecutors went back to the grand jury and had her re-indicted on charges of second-degree murder, aggravated arson and obstruction of justice. They also re-indicted Sumner and Baham, reducing their charges from first-degree murder to second-degree murder.

Baham’s trial is set for Nov. 10; Sumner’s is set for Dec. 8.

Follow Faimon A. Roberts III on Twitter, @faimon.