GUATEMALA CITY (Reuters) - U.S. software guru John McAfee, on the run from authorities in Belize seeking to question him in a murder probe, was arrested by Guatemalan police on Wednesday for illegally entering the country, that nation's interior minister said. McAfee, who had been in hiding for three weeks, crossed into Guatemala with his girlfriend, Samantha, to evade authorities in Belize who wanted to question him as "a person of interest" about the killing of fellow American Gregory Faull.