While he's awake and responsive, officials tell PEOPLE Austin Harrouff still can not speak, meaning investigators still have not questioned him about the murders of John Stevens and Michelle Mishcon

By Chris Harris
September 02, 2016 01:05 PM

The 19-year-old Florida State University sophomore accused of stabbing a couple to death and trying to eat one victim’s face remains unable to speak to investigators more than two weeks after the attacks, PEOPLE confirms.

Since his alleged Aug. 15 attack, Austin Harrouff has been a patient at St. Mary’s Medical Center in West Palm Beach, where he remains in critical but stable condition.

While he’s awake and responsive, officials tell PEOPLE Harrouff still can not speak – meaning investigators still have not questioned him about the murders of John Stevens, 59, and Michelle Mishcon, 53.

Officers will attempt to interview him again next week, a police spokesman says.

The couple’s bodies were found in the garage of their Tequesta home. Upon arriving at the scene, officers allegedly had to pull Harrouff off of Stevens. As he was allegedly biting Stevens, officers kicked Harrouff in the face several times, with no effect, police said.

According to police, Harrouff was allegedly biting Stevens’ face and had bitten into his abdomen.

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Police allege that before the killings, Harrouff consumed unspecified chemicals that he’d found in the couple’s garage. Doctors say he has injuries consistent with caustic chemical consumption, and last week, Harrouff’s father told PEOPLE his son’s organs were failing as a result.

A police source who asked not to be named tells PEOPLE that Harrouff has been unable to speak with detectives because the hazardous materials he had ingested burned the lining of his esophagus.

A Martin County Sheriff’s Office spokeswoman would not comment Friday on the source’s information regarding Harrouff’s throat injuries.

Police have speculated that Harrouff may have been under the influence of the synthetic drug flakka at the time of the alleged attack.

Harrouff tested negative for common street drugs such as heroin, cocaine, and marijuana, but more extensive testing is being performed by the Federal Bureau of Investigation to determine whether Harrouff was under the influence of bath salts or flakka.

Once he is released from the hospital, Harrouff will be charged with two counts of first-degree murder as well as attempted first-degree murder for allegedly stabbing the couple’s neighbor, 47-year-old Jeff Fisher, who tried fending off the couple’s alleged attacker, police say.

Harrouff also faces burglary and resisting arrest charges, police say.

Investigators are still trying to determine a motive for Harrouff’s alleged attack.

It is unclear whether a lawyer has been hired for Harrouff’s impending defense.