NEW HAVEN, Conn. — An animal research technician charged with killing a Yale graduate student raised suspicions when he began scrubbing floors after the crime and tried to move a box of bloody wipes from the view of an investigator, according to an arrest warrant released Friday.

The body of 24-year-old Annie Le was found stuffed behind a Yale research lab wall in September. An autopsy determined she was strangled.

Authorities say in the warrant that a green-ink pen found under Le's body had her blood on it, as well as DNA from suspect Raymond Clark III, on its cap. Police have said Clark signed into the secure building with a green pen on Sept. 8, the day Le disappeared.

The warrant says DNA from both Le and Clark was on a bloody sock found hidden in a ceiling.

The document also says Clark moved a box of wipes to hide blood spatters on it. Clark had a scratch on his face and left biceps that he said came from a cat, according to the affidavit.

Joe Lopez, Clark's public defender, declined to comment Friday.

Clark, 24, is charged with murder. Le vanished Sept. 8 from the Yale medical school research building where she and Clark worked, and her body was found five days later, on what was to be her wedding day. She was wearing surgical gloves with her left thumb exposed, according to the affidavit.

Clark has not yet entered a plea, but his attorney has said he will plead not guilty.

Clark said he knew Le for at least four months and did not socialize with her. He told police Le left the building 15 minutes before him carrying her notebook and two bags of mouse food.

The warrant, which does not offer a motive, describes a bloody crime scene and Clark's efforts to scrub floors.

Two days after Le disappeared, a graduate student showed a Yale police officer a box of "wipe alls" on a cart in a lab that had what appeared to be blood splattered on it. The officer watched Clark move the box of wipes and turn the box so that the bloody spots were not visible, authorities said.

"Once Clark moved the box of wipes, he then leaned up against the cart and made small talk" with the officer, the affidavit states.

The blood spatter on the wipes matched the victim's DNA, authorities said.

Clark later came back into the room and began scrubbing the floor with SOS pads and cleaning solution even though the floor appeared to be clean, according to the affidavit. He was also spotted "on the floor" inside Le's lab scrubbing the floor under a sink with a brush or cleansing pad, according to the affidavit.