PONTIAC, Mich. — Teenager Ethan Crumbley plans to pursue an insanity defense for his alleged role in the Oxford High School mass shooting that killed four students and wounded seven others. One of Crumbley’s attorneys, Paulette Michel Loftin, filed a one-sentence notification Thursday to Oakland County Circuit Judge Kwame Rowe and county Prosecutor Karen McDonald: “Please take notice that … Ethan Crumbley intends to assert the defense of insanity at the time of the alleged offense.” “This is the first step in a long legal road,” Loftin told The Detroit News on Thursday. “I expect he will be …