Jill Meagher was last seen early Saturday as she walked home alone from a bar in Brunswick, ABC reported. She had declined a ride from friends, though her husband, Tom, said she never made it to the couple's home.
Police said they arrested a 41-year-old man, whose name wasn't released. No charges have been filed against the man.
Police released CCTV footage Wednesday showing Jill Meagher walking home at 1:41 a.m. Six other people can be seen in the footage, including a man wearing a blue, hooded sweatshirt who approached and spoke to the missing woman.
Another man in the footage reported to police but said he didn't remember seeing Jill Meagher that morning.
Charlize Theron not engaged to Sean Penn 'yet'
Pistorius testifies he didn't consciously pull trigger when he shot girlfriend