I live on the 1400 block of 21st St NW. This morning at 8a I found all the cars on the block ticketed and a tow truck preparing to move another vehicle. The No Parking signs (posted yesterday morning) had been changed overnight or early this morning to read 6a-2p instead of the original 9a-2p. The block was cordoned off by a police van, and when questioned, the officer on the scene was completely unhelpful and said he had no idea who changed the sign nor when the signs were changed. I will obviously contest the ticket. I would urge my neighbors to contest theirs as well.