BALTIMORE (WJZ) — A Mississippi man accused of sending poison-laced letters to the president and other U.S. officials has been released from jail. Now the hunt continues for whomever sent the deadly substance.

Meghan McCorkell has more on these latest developments.

Charges were dropped against Paul Kevin Curtis after the U.S. Attorney’s Office says new information has been uncovered in the ricin investigation.

He was arrested last week and charged with sending ricin-filled letters to the White House and Capitol Hill. Now Paul Kevin Curtis is once again a free man.

“This past week has been a nightmare for myself and my family. My mother has suffered, as well as my children,” Curtis said at a news conference after his release.

The letters were sent to officials, including the president and Mississippi Senator Roger Wicker. They were intercepted at a federal mail processing facility in Prince George’s County.

Both letters were signed “I am KC and I approve this message.” Similar language on Curtis’ Facebook page led investigators to him, but no traces of ricin were found inside his home or in his car.

His attorney claims investigators are now looking at someone else.

“The government was able to basically find another suspect who we believe is the true perpetrator of this heinous crime,” said attorney Christi McCoy.

Hazmat crews searched another home in Tupelo, Miss. Tuesday.

The letters have triggered security scares across Capitol Hill, and one Tuesday at Bolling Air Force Base.

“This means we have individuals out there that are trying to cause harm to Americans, to people in leadership here in the United States,” Congressman Dutch Ruppersberger told WJZ last week.

Maryland Senator Ben Cardin’s office is just down the hall from Senator Wicker’s.

“It is somewhat unnerving when you know that there are people trying to cause that type of harm,” Cardin said.

And that person still hasn’t been caught.

In a statement to WJZ, Congressman Ruppersberger says, in part, “These acts were deplorable and whoever was responsible must be brought to swift justice.”

The charges against Curtis were dismissed without prejudice by prosecutors, which means they could potentially be reinstated.