MELBOURNE, Australia - A Melbourne couple returning home from vacation Monday were shocked to discover police about to hold a news conference at their house about their suspicious disappearance.

William and Heather Ostell's daughter, Angela, had not seen or heard from her parents since Thursday. She went to their house in the southeast Australian city and discovered the front door unlocked, their car gone and their dog home alone.

So she called the police and reported her parents missing.

Homicide detectives were holding a press conference Monday morning at the Ostell's home to appeal for information when the couple drove up.

Heather Ostell, 58, told reporters that they had taken a "spur of the moment" holiday and had not been able to reach their daughter to tell her.

"We had decided on Friday morning (to have a break) and we just let a couple of people know," she said. They arranged for neighbors to take care of their pet dog, and left the door unlocked by accident.

"I'll blame my husband for that. We're pretty security conscious," she said. "We just wanted to get out on the road and to get out of here."

The couple were shocked by the commotion at home and said they regretted worrying their daughter.

"I'll have to make my peace with her," Ostell said.