Here is the latest Iowa news from The Associated Press at 3:40 a.m. CST

IOWA CITY, Iowa (AP) — Before they arrested a farmhand in the death of Iowa college student Mollie Tibbetts, investigators scrutinized four other potential suspects during their five-week search. Newly unsealed search warrant documents show that those who drew police interest included a neighbor seen washing his SUV hours after Tibbetts vanished, a Nebraska man who ditched his vehicle in Iowa days later and an acquaintance who had recently erased his cellphone data. All have been ruled out as suspects.

CEDAR RAPIDS, Iowa (AP) — Cedar Rapids police say they have charged a man with murder, 39 years to the day after the killing of a high school student. Police announced the arrest Wednesday night in the Dec. 19, 1979, stabbing death of 18-year-old Michelle Martinko. Police arrested 64-year-old Jerry Lynn Burns on Wednesday morning in Manchester and charged him with first-degree murder. Martinko’s body was found just after 4 a.m. Dec. 20 inside her family’s car parked at a shopping mall.

IOWA CITY, Iowa (AP) — A Missouri farmer is accused of marketing $140 million worth of non-organic corn, soybeans and wheat as organic over 7½ years. The U.S. attorney’s office in Cedar Rapids, Iowa, charged Randy Constant with fraud on Wednesday. The Chillicothe, Missouri, man is expected to appear in court Thursday. Prosecutors say more than 90 percent of his product was non-organic grain purchased from others. Three Nebraska farmers have pleaded guilty in the alleged scheme.

OMAHA, Neb. (AP) — The latest Census estimates show that Nebraska’s and Iowa’s populations continued growing at a slow, steady pace over the past year. The U.S. Census Bureau released the latest state population figures as of July 1 on Wednesday.