A 21-year-old Troy man who suffered a suspected heroin overdose Saturday was arrested on felony drug charges.

Joseph T. Shellenberg, of 87 W. Lake Drive, was charged Monday with possession of heroin and the anti-anxiety drug alprazolam, Madison County Sheriff's Capt. Mike Dixon said.

Deputies were called at 2:50 a.m. Saturday to a St. Jacob home where they found Shellenberg being treated for a non-fatal overdose, Dixon said. A search of his backpack turned up several heroin capsules and alprazolam tablets.

Deputies arrested Shellenberg after he was released from a hospital.

If he wanted to avoid charges, Shellenberg's timing could not have been worse. On June 1, a new Illinois will go into effect that provides legal immunity to overdose victims who are found with small amounts of drugs.

"Under that new law, it will not be charged," Dixon said.

The law, which was signed by Gov. Pat Quinn in February, is meant to encourage people to seek medical help if they or their friends suffer a drug overdose. The law's critics said it provides a free pass to people who broke the law.

Dixon wouldn't give his opinion of the new law. But he said under the current law, these types of drug possession cases provide the courts with the perfect opportunity to impose drug treatment.

Shellenberg was one of several young heroin addicts that the Madison County State's Attorney's office tried to call to testify against Taylor Kennedy, 20, of Troy, who was acquitted May 10 of drug-induced homicide.

After Kennedy's attorney objected to these witnesses, prosecutors had to limit their number and their testimony. Shellenberg was among those witnesses who did not testify.

Shellenberg had told prosecutors that he had stopped using heroin in August 2011 following a stay in rehabilitation. He was on probation in Missouri and Illinois for drug possession charges.

The Madison County State's Attorney's office will review his case to decide whether to seek the revocation of his probation, spokeswoman Stephanee Smith said.

Shellenberg was being held Tuesday on $30,000 bail in the Madison County Jail.

Contact reporter Kevin Bersett at kbersett@bnd.com or 239-2535. Follow him on Twitter at twitter.com/KevinBersett