Alleged ‘Craigslist killer’ Philip Markoff, 23, ‘looked like basically any other medical student,’ according to a professor who worked with him frequently at Boston University School of Medicine.

The professor, who wished to remain anonymous, described Markoff as ‘calm’ and ‘pleasant,’ a student who ‘did what he was supposed to. Nothing jumped out about his character.’

Markoff grew up in upstate New York and was planning to marry fianc’eacute;e Megan McAllister, 25, this August. The two met while on rotation in an emergency room, according to their now-defunct wedding website.

The tame portrait of Markoff, who pleaded not guilty Tuesday to the April 10 armed robbery and kidnapping of 29-year-old Las Vegas prostitute Trisha Leffler and the April 14 murder of 26-year-old masseuse Julissa Brisman, is dissolving quickly in the face of media and police scrutiny.

While searching Markoff’s Quincy home, police found underwear belonging to Brissman and Leffler, police sources told The Boston Globe. Markoff found and arranged to meet both of his victims through online advertising site Craigslist.

Police also told The Globe they found a hollowed-out copy of ‘Gray’s Anatomy of the Human Body,’ concealing a handgun in their search of his apartment.

According to The Globe, investigators think Markoff, who was on his way to Foxwoods Resort Casino in Connecticut when he was stopped and arrested by a police cruiser in Walpole, was concealing a gambling problem.

Markoff is also under investigation for the April 16 attack in Warwick, R.I. of another prostitute who advertised on Craigslist, according to The Globe.

Another professor, who also wished to remain anonymous, called the situation ‘terrible’ and said he had gotten an email from MED Dean Karen Antman several days ago telling him not to talk to the media.

Staff writer Jenna Ebersole contributed reporting to this story.