HUDSON, Wis. (AP) – Security will be tighter at the St. Croix (KROY) County courthouse where jurors will decide whether a North Dakota man was sane when he killed his three young daughters.   A co-worker of Aaron Schaffhausen has been arrested on possible charges of threatening a witness. Authorities say the arrest stemmed from an incident Friday, the same day there was a security issue at the St. Croix County Government Center.  The Eau Claire Leader-Telegram ( ) says employees and visitors will be screened Monday as they enter the courthouse. Schaffhausen’s sanity trial is in its second week.   Schaffhausen has pleaded guilty to killing 11-year-old Amara, 8-year-old Sophie and 5-year-old Cecilia at their house in River Falls last July.

—      Information from: Leader-Telegram,