-LRB- CNN -RRB- -- Drew Peterson , the former police sergeant who authorities call the prime suspect in the disappearance of his fourth wife , Stacy Peterson , has been indicted on murder charges related to his third wife , Kathleen Savio , the Illinois state attorney 's office said . Drew Peterson was arrested Thursday on murder charges relating to his third wife , Kathleen Savio . Illinois State Police said Peterson was taken into custody about 5:30 p.m. Thursday after a traffic stop near his home . Police had staked out his home all day , said police Capt. Carl Dobrich , but waited for Peterson to leave to arrest him out of concern for his three children , who were inside the house . Peterson , through his attorney , denied any wrongdoing in either case . Wills County State 's Attorney James Glasgow said he believes the case is strong and said Peterson is being held on $ 20 million bond . `` This is an extremely grave and serious matter and it is reflected in the bond , '' Glasgow said . Peterson 's attorney Joel Brodsky told CNN 's Larry King he believed the bond was excessive and would seek a more `` reasonable '' bond , noting it was the most expensive bond he 'd seen in 10 years . Watch Peterson 's attorney address his client 's arrest '' Charles B. Pelkie , spokesman for the state 's attorney in Will County , Illinois , said a grand jury indicted Peterson in the murder of Savio , whose death had been ruled an accidental drowning . Brodsky said in a written statement that prosecutors wo n't be able to prove their case because `` he did n't do it . '' `` There is no evidence that links Drew Peterson to the death of Kathleen Savio or anyone else for that matter , '' Brodsky said . `` Drew did not harm Kathleen ; he has said so from Day One . We 're obviously disappointed a grand jury indicted him . But an indictment does not mean guilt . '' Pelkie said the grand jury continues to meet and is studying the possibility of charges in Stacy Peterson 's disappearance . Watch family members react to the arrest '' After Stacy Peterson went missing in October 2007 , media frenzy and police scrutiny on Peterson revealed Savio had died mysteriously a few years earlier during a nasty divorce . Savio died just before the division of the marital assets was finalized , making Drew Peterson the sole beneficiary . Savio was found in the dry bathtub of her home . At the time , the death was ruled an accidental drowning . But her family continued to insist that Savio died as a result of foul play . The investigation into Stacy Peterson 's disappearance brought renewed interest in Savio 's death . Authorities exhumed Savio 's body , further tests were conducted , and her death has now been ruled a `` homicide staged to look like an accident . '' Brodsky told King he believes the case has always been about circumstantial evidence and that he will bring a pathologist to trial who will say Savio died from an accidental drowning . `` I think the jury 's going to see that , in fact , this always has been an accidental death and still is an accidental death , '' Brodsky told King . Kathleen Savio 's brother , Nick , told CNN affiliate WLS-TV he received a call from his sister saying Peterson had been arrested . Watch police arrest Peterson '' `` The state police had been telling us the day was coming , '' he told WLS-TV . `` We kept hearing it for about eight months . I 'm almost in tears here . It 's been so hard for our family . '' `` Hopefully , we 'll get the justice we 've always been waiting for . '' Martin Glink , attorney for the Savio family , said they were hopeful the grand jury felt there was enough evidence to charge Peterson . `` We 're very happy that the wheels of justice have continued to move and they are pointing in his direction , '' Glink told WLS-TV . The news was also bittersweet for Stacy Peterson 's family , who continue to wait for news about her disappearance . `` We have anticipated this coming . We have dreamed about it . We have been patient over it , '' Pam Bosco , spokesperson for Stacy Peterson 's family told WLS-TV . `` Now that it 's here , it 's almost a little bit calm . We 're waiting for the storm to calm now . The calm before the storm . '' Bosco said while she had not heard about any charges relating to Stacy Peterson 's death , she was hopeful those charges would follow . `` We always said from the very beginning that Kathleen and Stacy had one thing in common -- and that was Drew Peterson , '' she said . `` So , hopefully , we 'll have news soon about Stacy , too . '' Ernie Raines is also relieved about the arrest . His daughter , Christina Raines , is dating Peterson and was living with him before his arrest . Ernie Raines told CNN 's Anderson Cooper he was with his daughter and Peterson as recently as last week , when they talked about going to Las Vegas , Nevada , and getting married . Thursday night he spoke with his daughter after the arrest . `` My daughter was terrified , very emotional , upset , '' Ernie Raines said . `` And I tried to tell her from the beginning that this was going to happen , be prepared . '' Ernie Raines said more than anything , when he heard about the arrest , he was relieved . `` I 'm glad justice finally came -- before he hurt my daughter , '' he said . Police put Peterson 's three minor children in the custody of the state 's children and family service department . His adult son was contacted , at Peterson 's request , to take them , according to Capt. Dobrich . Dobrich said Peterson cooperated with police during his arrest . CNN 's Susan Roesgen contributed to this report .