Neighborhood newsgroups are buzzing about suspicious incidents (such as this one) of a gray car circling around the Glen Canyon/Berendo/Pepper Dr. area, apparently looking for freshly-delivered UPS packages.

One recent sighting said:

I noticed a noticed a small, gray auto with two passengers. The
driver was a young girl and the passenger (black pants, white
sweatshirt, black wool cap). They’d drive about four or five houses,
the passenger would get out, walk up to a house, and go back to the car.

Another report says:

At about 1:50 p.m.(Wed. Dec. 19) I was returning from the market and noticed a gray two
door station-wagon type car with two men slowly driving up the street
close to the curb.  They would drive up a few houses and then back up a
few houses, with the man on the passenger side looking out the window.

I parked in my driveway, got a pad and paper and started walking down my
driveway.  The driver rolled down his window and asked me if anything was
wrong.  I said, "Not yet," and kept walking behind the car to get the
license.  They drove away up to near the corner of Glen Canyon and
Pepper.

I went inside and called the Sheriff’s.  Then, when UPS came back to my
house to deliver a package, I told the drivers and they alerted their
headquarters so that other drivers could be alerted as well.

The license plate of that car was recorded as 5TLC777.  If you see anything suspicious. call the Altadena Sheriff’s Station at  626-798-1131.