A University of Colorado psychiatrist treating suspected theater shooter James Holmes rejected an offer to put him on a 72-hour psychiatric hold after he told her on June 11 that he fantasized about killing “a lot of people,” a source told The Denver Post.

Six weeks later, authorities say, Holmes carried out his fantasy, killing 12 people and injuring at least 58 others in a massacre at the midnight premiere of a Batman movie at an Aurora cinema.

The newly revealed development in the theater shooting was first reported by 7News and later confirmed to The Denver Post by a source close to the investigation who asked to remain anonymous.

Lynne Fenton, the psychiatrist who treated Holmes, has not publicly revealed what Holmes told her that made her notify the campus-wide threat-assessment team that she helped create years before.

CU police Officer Lynn Whitten asked Fenton whether she should apprehend Holmes and place him on a 72-hour psychiatric hold, The Post’s source said. Fenton, who has the authority to ask for a hold, rejected the idea, according to the source. Holmes was in the process of quitting the CU neuroscience graduate program where he had been a student since June.

Holmes, 24, is being held without bond at the Arapahoe County Jail. His next court appearance is scheduled for next week.

In other developments in the theater shooting case on Wednesday, the university released two CDs to news outlets containing nearly 3,800 e-mails from the university’s e-mail system that reference Holmes or that were sent to or by Holmes from his two university e-mail accounts.

The university removed any e-mails that deal with Holmes’ mental health, the crime and any personal communication involving Holmes. A number of e-mails from Holmes’ account around June 11 — when Holmes is alleged to have made threats to a professor — were redacted.

Most of the messages released were unexceptional and unrevealing. However, one comment from a professor in CU’s computation bioscience program sent the morning after the shooting said Holmes had a brief romance with a fellow graduate student on the University of Colorado’s Anschutz Medical Campus months before he is accused of going on a murderous rampage.

“She, fortunately, it turns out is in India right now,” the e-mail says. “She knows, and is pretty freaked out.”

The messages show the mundanities of Holmes’ life on campus — in one from November 2011, he requests an “NRSC 7610 enrollment form” — and the chaos that engulfed the school after the shootings at the Century Aurora 16 theater.

“As you all know by now,” said an e-mail sent to students, including Holmes, the morning after the shooting, “a former student in the neuroscience Ph.D. program was responsible for the horrendous tragedy at the Aurora movie theater this morning.”

Holmes withdrew from the program earlier this year after he failed to pass a critical exam. Prosecutors allege he was already stockpiling weapons and ammunition.

Messages in his inbox were mostly announcements or communications from the university or messages from list-serv accounts that he had subscribed to.

In one e-mail Holmes sent in February, he asked a professor if there were openings in the professor’s lab.

“I’m a first-year neuroscience graduate student and am interested in learning more about your work identifying genetic factors in neurogenic diseases,” Holmes wrote.

He signed the e-mail, as he did others, “Cheers, James Holmes.”

Mentions of Holmes multiplied in e-mails following the shootings. Faculty and staff members sent messages to one another wondering if the rumors were true that he was a student at the university. Then scores of e-mails from media outlets poured in wondering the same thing.

Finally, CU released an official statement, a photo and began discussing what to do about all of the requests. Reporters were showing up at professors’ homes, calling their relatives and inundating CU with questions. One professor said that his mother had 12 phone calls from reporters.

“Do NOT release any information,” said one e-mail. Another advises faculty and students not to post anything on Facebook or Twitter about the incident.

Even though he was in custody, Holmes also received media requests in his inbox.

“Question for you,” a reporter with Yahoo News wrote Holmes the morning of July 20, “in light of today’s tragic shooting in Colorado, wondering if you’ve been inundated with requests (like this one) since you share the same name with the suspect. Would you be available for a brief interview.”

Jeremy P. Meyer: 303-954-1367, jpmeyer@denverpost.com or twitter.com/jpmeyerdpost

Staff writer Karen E. Crummy, Kieran Nicholson, Colleen O’Connor, Ryan Parker, Jordan Steffen, Sadie Gurman and Kirk Mitchell contributed to this report.