Albany great-grandmother attacked in her own home

A great-grandmother has been threatened by a teenager armed with a knife in her home in Albany, south-east of Perth.

Margaret Triplett, 78, told 9NEWS she was forced to keep herself calm when she heard he back window smash on Tuesday night.

She ran to the kitchen and called triple zero - but before she was connected through to police the 16-year-old allegedly grabbed her by the neck, ripping the phone out of the wall.

He then pulled out Margaret's favourite carving knife, featuring a 20cm-long blade.

"I could have been killed he kept saying I'm going to kill you and he had this big knife," Mrs Triplett said.

"He put his arm around my neck and said I'm going to kill you."

It is alleged the teen then fled and smashed two sets of windows at other nearby properties before being arrested shortly after midnight.

9NEWS understands he was tasered by officers at a nearby carpark during the arrest.

Mrs Triplett lost her husband just a few months ago, and says now she's uneasy living alone.

"I'm not angry, I'm just really hurt that someone could come in and do that - there's no point in that," she said.