"You're going to have a lot more problems down the road if you can't take any [expletive] criticism, Johanna," one of the e-mails said, Justin-Jinich told police, according to a complaint she filed on July 17, 2007.
Both Justin-Jinich and Morgan were interviewed by the police, but Justin-Jinich declined to press charges, according to the police and NYU spokesman John Beckman.
In the time Morgan spent hiding from authorities -- who had reportedly questioned him at the scene but let him go, according to the Hartford Courant -- officials had announced a $10,000 reward for information that led Morgan's arrest, $5,000 each from the U.S. Marshal's Service and Wesleyan.
Police and university officials had urged students to stay inside after finding Morgan's journal, in which he allegedly made threats to Wesleyan students and its Jewish community. Morgan also allegedly wrote in his journal, discovered in his car near the crime scene, about wanting to rape and kill Justin-Jinich, the Associated Press reported.
"We are all breathing a little easier with this news," university president Michael Roth said in a statement.
Morgan said his brother has not displayed anti-Semitic behavior in the past. "My brother was a very sweet person and had a big heart, and I hope he's OK," he said.
ABC News' Rich Esposito and The Associated Press contributed to this report.