Transcript for Body found in search for missing Iowa jogger Mollie Tibbetts
Reporter: The sh for missing mollie ti come to a tragic end today. The body was discover early this morning in a farmld southeast of Brooklyn, io we believe it to be the body of ie Tibbetts she was found in a cornfield, and TRE were corn stalks placed over T top of her. Reporter: Tonight a suspect in study, 24-year-old crisn Rivera. Police say river them to her body and confessed the murder. Thee will be proted by the iow attorney general's are prosecutio division and first degree murder carries a penalty of life without the possibility of parole. Orter: According to orities, Rivera encount mollie Tibbetts near the interson of boundary and middleeets in eastern ooklyn WHE she was out in E actually tells us he ran alongside of her or behind her. And then at one point he tells us that mollie grabbedahold O he phone and said, you need leave alone, I'm goingo call the police. Her wn. Reporter: According to authorities,a then nicked and got mad. Heells ust some point in time he B out and then he comes toear a intersection - to aornfield in Guernsey ware he Dra Tibbetts on foot for0 meters and ler fa andedin cornleaves. No one has sth was a sexually-driven crime but it certas pattern of dozens and dozens of se predator ck-type crimes. Repr: Authoritiesay an autopsy iseing done and have not yet released a cause of death. Rivera has been charged wit tegree murder. A sop at university of , me beloved by mily and friends. With a bubbly personality and sparkle in her eye. Seen her videos sd with ABC news. 20-year-old universf tudent mis since July 18th when she went out for an evening jog vanished. He boyfriend saying his last mmunicationh her was a Snapchat opened around10:00 P.M. I look at messages, she hadn't opened or read a singne of em. I startedowing red flags and tedal everybody to S if they'd go contact with her. Everybody W come up blank. Reporter: When mollie did N show up to work the nextday, her abs raised alarm. One of work friends called me. And said she didn't com in today, S didn'tl in. I was like, th not like her. Eporter: Her parents and boyfriend growing desperate to brg herhome. We miss U. E looking for you. We will never stop. Reporter: Her disappearance shocking quiet, tight-knit community oklyn, Iowa. A record-breakingrly ,000 reward for information leading to safe turn. In a communiikebrooklyn, everyonenows everyone, everybod sees everything. Someone knows what's end. E believe that mollie is still aliv and if someone has abductedher, we reading with Y to please release her. I just W H home. Orter: Communitybers combing through cornfi, us T accompany them to STA fair E they were handing out flyers. Lessyou. Thank you very much. Nvestigato received more than 4,0 tips sincemid-julynd had between 30 T 4 officers working on mollie's case, inclu help frhe FBI. We have notd down at all the investigative process. Reporter: Ultimat W now ow it was sveillance video from eastern brookn that police say led them to a Chevy nked to ra. The vid was critical, that it way. Reporter: According to law rcement, riva had been rkingally in the area for several ye officials say he was an undocumented grant, a detail that Iowa governoim Reynolds quicklyweeted about,ing inpart, we are angry T a broken immigrattem allowed a predator this to liven R community. Tonight a a rally in west Virginia, pdent trump talking T Rivera's arrest and his immtionstatus. You heard about today with thellegal alien coming in very sadly, froxico. And you saw what happo that incredible beautiful young woman. Should have neverhaed. Reporter: But ading to a 2018 cato institute study, undocument immigrants are 25% lessik convicted of homicide than native-born amerans. Legal irantse 87% less likely. His gentleman's behavior had nothing to do wh his immigration at it to do with hiswn urges and desires and fas. Reporter: Tonight the university of Iowa where mollie was studying psychology issuing thisstatemt. We are deeply saddened that we've lost a member of T univ of Iowa community. Our thoughts are mollie Tibbetts' family, ends, a clates. Mollie would have B a rising or. Local residents echoing their sorry. E hope. We hade that somebody was Ju holding her and that somethinust went wrong and they would come to their senses D bring H home. Wet - we had hope. Reporter: F "Nightline," I'mx Perez inrooklyn, Iowa.
This transcript has been automatically generated and may not be 100% accurate.