More than a year after the Department of Justice started looking into the fatal shooting of Ramarley Graham, the teen killed by a police officer inside his Bronx home in 2012, his family is asking why the only two witnesses have yet to be interviewed.

Graham's mother, Constance Malcolm, will call for a full investigation into the 18-year-old's death today, begging for closure.

"I don't know what they're waiting for," Malcolm said Tuesday. "Every day I get up and I wish my son was here. I still can't get any answers to what happened to my child."

Graham was shot and killed after being chased by Richard Haste and other officers into his Bronx apartment where he tried to flush marijuana down a toilet. Haste has said he believed Graham was armed at the time. No weapon was recovered.

Graham's grandmother and younger brother, who was 6 years old at the time, were home.

After a series of failed grand jury actions in state court the case against NYPD Officer Richard Haste stalled.

In August 2013, the United States Attorney's office for the Southern District of New York said they would review the case, but Malcolm said she has yet to hear from anyone.

The U.S. attorney's office did not immediately respond to a request for comment.

Attorney General Eric Holder opened an investigation into another shooting death of a teen, Michael Brown, in Ferguson, Mo., promising it will be "thorough and fair." Holder will travel to the St. Louis suburb Wednesday, according to a statement.