Alice Gross, the 14-year old London girl who went missing during the last week of August, has still not been found, and her family issued a plea for information regarding the teen as Scotland Yard focuses their investigation on a man with a violent past.

Arnis Zalkalns was spotted biking on a path shortly after Gross was last seen in the same area, and police are searching for him for questioning. Zalkalns was reportedly convicted in 1998 of stabbing his wife to death and was sentenced to seven years in prison. He has not been seen since September 3.

“Alice has been missing for four weeks now. We are desperately concerned about her welfare and worry constantly about what may have happened to her. We are appealing to Alice. If you are out there, to come home where you belong…. We want to be a family again,” the Gross family said in a statement.

Alice has been missing since August 28, when she was seen walking on a path under Trumpers Way bridge towards Hanwell. Locals have rallied around the family to aid in the search, and investigators have even recreated Alice’s walk along the canal, saying she has a distinctive gait that might be remembered by anyone who saw her that day.

“Just as Alice reached the [Trumpers Way] bridge it started to rain heavily. Think back and try to remember if you were out and about in that area that afternoon. It was during the summer holidays and the canal is a really popular place locally. We know that Alice loved the rain, so she probably would have kept walking in it rather than seek shelter. There are many paths and turn offs from that canal towpath. We don’t know the route that Alice took, so please think back to that Thursday four weeks ago and call us if you can help,” Detective Superintendent Carl Mehta told BBC News.