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

DES MOINES, Iowa (AP) — The arrest of a Mexican farmworker in the death of an Iowa college student renewed calls to change immigration laws, but it also focused attention on the immigrant workers whose labor is essential to agriculture. Hours after authorities found the body of Mollie Tibbetts, some Republican politicians expressed outrage that the suspect had been able to live illegally in the U.S. for years. Farm groups were more muted, reflecting the difficulty in hiring for dairies and slaughterhouses.

BROOKLYN, Iowa (AP) — A medical examiner says the Iowa college student who was allegedly abducted by a stranger last month died from stab wounds. Authorities say preliminary autopsy results show 20-year-old Mollie Tibbetts was the victim of a homicide who died from “multiple sharp force injuries.” State medical examiner Dennis Klein says that finding means a sharp-edged or pointed object such as a knife was used to attack Tibbetts.

DES MOINES, Iowa (AP) — Cindy Axne, the Democratic candidate for Iowa’s 3rd District congressional seat, is calling on Rep. David Young to reject a telephone poll that includes a statement about the death of University of Iowa student Mollie Tibbetts and misstates Axne’s position on immigration. The 15-minute poll asks voters whether the statement would affect their vote.

DAVENPORT, Iowa (AP) — An eastern Iowa woman wanted in connection with the death of her 5-year-old son has been arrested on a charge of first-degree murder and her former boyfriend is still at large. The Quad-City Times reports that 24-year-old Jacqueline Majanise Rambert, of Davenport, was taken into custody Tuesday in Chicago. Murder warrants were issued for Rambert and 26-year-old Tre DeSean Henderson for the death of 5-year-old Ja’Shawn Bussell.