An MIT campus police officer was killed late Thursday from multiple gunshot wounds, and that was only the start of a crazy several hours that included a link to Monday’s bombing of the Boston Marathon and to a man missing from Brown University since mid-March.

An attack on a disabled man Monday at the T’s Downtown Crossing stop — described by police as happening for “no logical reason” — led to the arrest and arraignment of a woman with Cambridge and Somerville addresses, as well as two men.

Community Supported Art, which links local artists to local buyers, is back for a second round with a new crop of nine area artists, including two from Cambridge.

Three Cambridge startups are among the eight to be featured at Monday’s Web Innovators Group gathering, the 27th such event intended to get tech entrepreneurs and venture capitalists mingling.