Dayton mass shooter Connor Betts dropped out of college because he said he didn’t “have the maturity” to handle it, according to a new report.

Betts, 24, withdrew from Wright State University in the spring of 2014 after attending for just a few months, according to an email he sent to his academic adviser at the time, obtained by the Cincinnati Enquirer.

“I write to inform you that I must withdraw from Wright State, as I do not yet have the maturity to handle college,” his note said.

His unofficial transcript, obtained by the paper, indicates that he was enrolled in the psychology department. His fall schedule included an introduction to psychology and an introduction to sociology class, which he appeared to have taken before withdrawing, according to the report.

He was also placed on academic probation at the end of his fall semester, the paper reported.

Betts’ 22-year-old sister, Megan, also attended the school. She was among nine people killed Aug. 4 when Betts opened fire in the city’s Oregon District. Fourteen others were wounded.

Investigators have said that Betts embraced “very specific ideologies” ahead of his rampage but refused to elaborate on the exact nature of those beliefs.

His ex-girlfriends have reported that he exhibited several red flags in the months and years before the shooting.