His father worked on the Trace estate, but he was killed in a motor accident, his wife with him. Michael and his sister were supported by Henry Trace and raised by a nanny in an estate cottage
He was a skilled artist, but almost entirely misanthropic. He was also a skilled actor, he'd had to be since he and his sister, Katherine Lacey, had been having an incestuous affair since they were teens and had to constantly cover it up.
In a long game, they conspired to murder Bella, the wife of the local land owner, Henry Trace, during a shoot. He separated her from the group, setting her up to be shot by Katherine. Katherine then slowly wormed her way into Henry's affections and the wedding was scheduled. Speculation was that he would not have lived more than a year after the nuptials.
After their plot was found out, as part of a murder/suicide pact, he and Katherine went into the woods where he shot her and then himself. The instrument of death in both cases was a shotgun.