SHERMAN, Tex. (KXII) -- In a plea deal with prosecutors, a person of interest in the murder of former Sherman High student Mikayla Mitchell pleaded guilty in federal district court for dealing several pounds of street drugs.
Mitchell's body was found in a city park pond in July 2017. She was reportedly stabbed multiple times. No one has been charged with Mitchell's murder.
Darnell Dwight Smith's arrest on federal drug charges came at the same time he was a person of interest by police in Mitchell's killing and her kidnapping days earlier. Mitchell was 17 years old at the time of her death.
"Mikayla was involved in some sort of kidnapping, abduction and assault," Dallas Detective Steven David said in a telephone interview.
David said Mitchell claimed she was assaulted and kidnapped after escaping to a convenience store in Merkel, Texas.
"Where she was taken from Midland, Texas to Merkel, Texas where she was able to escape from the car and run into the convenience store," David said.
Investigators said the suspects fled the scene and one of them was Smith, also known as "Slick Rick."
"Next week she was found murdered in Dallas from homicidal violence," David said.
Smith will be heading to federal prison after pleading guilty last week to dealing several kilos of cocaine, methamphetamine and marijuana from his home in Sherman.
Mitchell is the stepdaughter of local pain management doctor, Dr. Howard Gregg Diamond. Days before her death, Diamond was arrested by federal authorities on apparently unrelated drug charges of his own. Accused of prescribing pain medication for no medical reason, resulting in the overdose deaths of at least seven people.
David said the doctor is not a person of interest in Mikayla's death.
"The only people who know are the ones that did it," David said.
Diamond has pleaded not guilty to his drug charges and he remains in Fannin County Jail awaiting trial in federal court.
Mitchell's family was asked for comment but has not yet responded.
If you have information regarding Mitchell's homicide, contact Det. David of the Dallas Police Department at 214-671-3627.