(Credit: FBI)

(Credit: FBI)

CHICAGO (CBS) — The man suspected of fatally shooting 12 people at the Navy Yard in Washington D.C. on Monday has ties to the Chicago area.

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Aaron Alexis, according to the Pentagon, was a naval trainee at the Great Lakes Naval Training Center in North Chicago in 2007.

He was at Great Lakes for a short time, from May to July of that year.

Alexis was a full-time navy reservist when he left service in 2011.

According to CBS News, Alexis, 34, had been arrested at least twice previously: once in Seattle for malicious mischief, and once in Fort Worth in 2010 for discharging a firearm in public.

Investigators said they had not established a motive for the shooting rampage.

The area that was targeted, known as Building 197, was part of the headquarters for Naval Sea Systems Command, which buys, builds and maintains ships, submarines and combat systems. About 3,000 people work at the headquarters, many of them civilians.

Witnesses described a gunman opening fire from a fourth-floor overlook, aiming down on people in the first-floor cafeteria. Others said a gunman fired at them in a third-floor hallway. It was not clear whether the witnesses on different floors were describing the same gunman.

Alexis was born in New York City and he enlisted at Great Lakes on May 5, 2007.

According to the Pentagon he served as an aviation electrician’s mate, 3rd Class.

He received the National Defense Service Medal and Global War on Terrorism Service Medal.

He served in Fort Worth from February 2008-January 2011.

CBS 11 reporter Arezow Doost reports that Alexis’ friends in Fort Worth said the gunman was a gentle man. He said he did own a handgun and a concealed gun license.

However, a witness involved in Alexis’ 2010 gun arrest said she was terrified of him.

Police were called to an apartment complex in the Fort Worth area after a woman said someone shot a hole through her floor and ceiling. Visibly shaken, the woman told police she thought her downstairs neighbor — Alexis — was the culprit.

Alexis had called police several times on the woman, according to the police report, and complained about loud noise coming from her apartment. But each time police did not find the woman at fault.

Several days prior to the incident, Alexis’ neighbor said he confronted her in the parking lot about making too much noise. She claimed that she was “terrified” of Alexis and felt that he was intentionally trying to intimidate her. So much so, that she relocated three times, according to the report.

Alexis told police that he was cleaning his gun while he was cooking, that his hands were slippery and it went off.

No one was hurt in the incident and charges against Alexis were dropped.

(©2013 CBS Local Media, a division of CBS Radio Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)

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