"I think the plea is a slap in the face," the victim's mother said

A former navy sailor has been sentenced to 40 years in prison after pleading guilty to the 2016 killing of a transgender woman in Mississippi with whom he’d had a sexual encounter, a Jackson County Sheriff’s Department spokesperson confirms to PEOPLE.

Dwanya Hickerson, 21, pleaded guilty on Thursday to killing Dee Whigham in a St. Martin, Mississippi, hotel room last July 23, the Associated Press reports. Autopsy results show that Whigham, 25, was stabbed at least 119 times. Many of the wounds were to the victim’s face, and her throat was slashed three times, the spokesperson confirms.

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Hickerson also pleaded guilty to robbery for taking Whigham’s purse and cell phone, the spokesperson says. Jackson County District Attorney Tony Lawrence recommended he serve 40 years for the count of second-degree murder and eight years for the robbery, The Clarion-Ledger reports.

Hickeron could have faced the death penalty for the original capital murder charge.

As part of the plea, Hickerson apologized to the victim’s family. The spokesperson confirms Hickerson said, “I’d like to apologize to the victim’s family. If I could take it back I would.”

Image zoom Source: Dee Whigham/Facebook

Hickerson, a native of New Orleans, enlisted in the Navy in Georgia on Sept. 15, 2015, and was studying to be a weather forecaster at the Keesler Air Force Base in Biloxi, Mississippi, the Sun Herald reports.

Jackson County Sheriff’s Deputy Leo Allen said a surveillance video showed Hickerson and Whigham walking together into a Best Western Hotel room around 8:30 p.m, the AP reports. He said the video showed Hickerson leaving the room alone about 23 minutes later, with his shirt around his neck, WLOX-TV reported. Before leaving the room, he took a shower, and left the water running.

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Whigham’s friends found her body around 9:45 pm and called 911. The friends told deputies they did not know Hickerson.

Hickerson said in court that had been chatting online for a couple of months with Whigham and decided to meet her when she said she was in Biloxi with friends, according to the AP. After they a sexual encounter, she revealed she was transgender.

“I lost. I lost it,” Hickerson said Thursday, the AP reports.

Hickerson will have to serve eight of the 15 years for a robbery charge, and 35 of the 40 years for the murder charge.

Whigham’s mother, Vickie Blackney Whigham, criticized Hickerson’s sentencing, the AP also reported.