This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

(Memphis) It’s been three years since the murders of two post office employees rocked the town of Henning.

Even though investigators had a confession from Chastain Montgomery saying he and his son did the crime, it wasn’t until Friday U.S. Attorney Ed Stanton told a federal judge he will seek the death penalty for Montgomery.

“I don’t think it was really a surprise to us. That is sort of the nature of these types of cases,” said Michael Scholl, who is Montgomery’s attorney.

Scholl is already laying out his argument to keep his client alive, “We presented records, filings in court about the mental disability of our client. There’s been I.Q.  scores below 65.”

He says mentally disabled people can’t be put to death.

Investigators say Montgomery confessed to the crime, saying he and his son robbed the post office, with hopes of getting thousands of dollars.

When they only got a few dollars, they got angry and shot workers Paula Robinson and Judy Spray.

For months, the two eluded police, until the younger Montgomery was stopped for another crime.

Officers say he opened fire on them and they shot and killed him.

Chastain Montgomery was arrested when he came to the scene.

Officers say the two had the same guns used in the Henning murder.

Family members on both sides were at the hearing Friday, but had no comment.

We are told this trial could take years because there are several sets of attorneys and experts who will be brought in to testify on Montgomery’s mental state.

The hearing is set to start September 16, 2013.

Montgomery is charged with:

Two counts of killing employees of the United States

Robbery with a dangerous weapon.

Using a firearm to commit a crime of violence. (10 years to life.)

Two counts of Killing Paula Robinson and Judy Spray.