Neighbor Reports "Shifty Character" In The Neighborhood

We received this email:

I wanted to alert you to a shifty character in the neighborhood. I live on 42nd Avenue near NE 41st Street. On Sunday my husband and daughter left the house around 10am.  Shortly thereafter, I left the house for a run.   

As  I started to run up the NE 41st Street hill, I saw a younger man on a bike waiting at the bottom of the street.  As I ran up the hill he started riding down the sidewalk.    

I had an uneasy feeling about him, and walked back down the hill and watched him.  He stopped in front of my house.  He looked back and saw me watching him and immediately started pedaling down the sidewalk.  He looked back at me over his shoulder 3 or 4 times as he road south on 42nd Avenue NE.  

I went in to the alley to see if he would ride up the alley, but he had disappeared. I warned my neighbors about him. He was around  late 20's.  Dressed in dark clothes, wearing a large bright red backpack. No helmet.