Inference may be a bit strong. The reports are that UNC hired lawyers/investigators who asked questions not just about Mike, but also about Steve. These investigators asked direct questions about Steve and drugs. The questions about sex were "unrelated to Steve Belichick' as per the following quote.
Lawyers conducting the UNC probe focused a series of questions on Steve Belichick, according to people who were interviewed. The people said they were also asked about whether Steve Belichick had used drugs at the university’s facilities or if they knew of anyone who had seen him do so. Assistant coaches can be fired for cause if it is found that they used or distributed illicit drugs, according to UNC employment contracts.
Unrelated to Steve Belichick, sources also told WRAL that the lawyer asked about reports of a purported sexual relationship between a female recruiting staff member and at least one UNC player. The people also said they were asked about similar possible relationships between assistant coaches and recruiting staff.
Lawyers investigating UNC football questioned people about allegations involving assistant Steve Belichick and, separately, about a possible sexual relationship between at least one employee and at least one player, people familiar with the probe tell WRAL. GM Michael Lombardi resigned Thursday.
www.wral.com
So far Steve is still UNC's defensive coordinator and is on medical leave. No one has said what the nature of the medical issue is or how long he'll be out.