HOUSTON – A 14-year-old girl with special needs died in October 2016 from the toxic effects of blood pressure medication, an autopsy report shows.

A fourth person has been arrested and is accused of having a role in her death.

On Nov. 14, Harris County deputies arrested Tommieretta Gunner, Marreissa Jones and the child's father Anthony Jackson, according to a press release from the Sheriff's Office.

On Tuesday, Keyonna Gunner was arrested and taken to the Montgomery County Sheriff's Office Jail after deputies said she used a stun gun on the child while at the residence.

Surveillance video inside the residence caught the abuse of the 14-year old child, according to the release. The abuse included numerous individuals using a stun gun on the girl over a span of several months.

"Approximately 12 minutes after leaving her room, A.T. returns and Jackson follows her in with the stun gun and shocks A.T., A.T. jumps away from the stun gun and appears fearful of it. It appears as if A.T. was layering her clothing in order to minimize the effects of the stun gun shock," one investigator said.

Jackson is seen using the stun gun seven times and threatening her at least 15 other times over that period, the release states. Video also reportedly shows Tommieretta Gunner and Jones "giving the child two different high blood pressure medication over a three-week period," the report says.

Jones worked for a home health care provider and was assigned as a caretaker for the child, according to the release.

The girl was never prescribed blood pressure medication, and her mental and physical attributes change significantly after Tommieretta Gunner, Jones and Jackson gave it to her, the release states.

Detectives said the impact of the medication on the girl can clearly be seen in some of the recordings.

"In many of the videos, A.T. is observed to be able to maneuver around her home, feed herself, dress herself, and perform other basic functions. In some Videos it appears that A.T.’s mental and physical faculties are highly impaired."

Tommieretta Gunner and Jones are charged with first-degree felony injury to a child charge, while Jackson was charged with third-degree felony injury to a child, according to the release.

Jackson, Jones and Tommieretta Gunner are due back in court Nov. 29.

The Montgomery County Sheriff's Office is still investigating the case and is asking anyone with information to contact the Montgomery County Sheriff's Office at 936-760-5800 or Crime Stoppers at 1-800-392-STOP (7867) and refer to case #16A190412.