CHICAGO (WLS) — The individual accused of a targeted antisemitic fatal attack in the U.S. capital allegedly transported the murder weapon on a flight from O’Hare airport on Wednesday, according to court documents.

Elias Rodriguez, 31, of Chicago flew from O’Hare to Reagan National in Virginia.

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He declared his firearm in checked baggage on the Wednesday flight.

He also bought a ticket three hours before it started to the Washington, D.C. event the couple he allegedly killed attended, according to the FBI.

“In terms of flying with a firearm legally, I must emphasize it was carried out lawfully as he declared it as checked baggage,” mentioned ABC7 Chicago law enforcement specialist Bill Kushner. “Such scenarios are a major concern for law enforcement. These lone wolf terrorists operate below the radar, don’t exhibit any obvious signs publicly, have no criminal history, and are the ones that pose the greatest threat.”

Rodriguez was taken into federal custody on Friday, charged with the murder of two employees from the Israeli embassy in Washington.

Yaron Lischinski and his girlfriend, Sarah Milgrim, were both killed.

The two were planning to get engaged on an upcoming trip to Jerusalem.

Authorities say the couple were leaving the capital Jewish museum when Rodriguez approached a group and opened fire.

The gunman reportedly shot the couple from behind, continuing to fire even after they collapsed.

Moments later, police say Rodriguez went into the museum. Witnesses say he tried to blend in with other victims.

“I was worried for him, thinking, you know, he might have experienced something,” witness Yoni Kalin said.

“I was trying to comfort him, and my friend offers him some water. He reaches into his backpack and pulls out a keffiyeh, and says, ‘I did it. I did this for Gaza. Free Palestine,'” witness Katie Kalisher said.

Lischinski’s coffin arrived in Israel Friday.

And Jewish leaders in Chicago spoke out again Friday to denounce the shooting.

Rodriguez faces a list of federal charges, including the murder of foreign officials

He did not enter plea during his first court appearance Thursday.

His next court appearance is June 18.