7 year old wonderfu lab starts biting and peeing in house

Question
We have a male 7 year old neutered black lab who has changed behaviour in the last week.  We got Becker as a lab rescue at 10 months just before we had our first child.  We did training with him and he is a GREAT dog with both of our kids and other dogs and people.  He comes to work with me and is with me all day, gets lots of time to play with all of us, get exercise and plays ball daily and has seemed to be a really happy dog.  Withing the last few days things have changed as he bit a man on a walk and tore his pants, within 5 minutes tried to bite another man and tonight peed on my daughters floor for the first time in probably 5 years.

I'm really worried about him.  Any ideas what could be the problem?

Answer
It is unusual for a dog to change like that.  Unless there has been some change in your household making him more protective, I would have the vet give him a good physical, explaining the personality change.  

If the vet doesn't find anything, you may need a behaviorist to see what is happening and how to correct it.  Perhaps the vat can help you find a good one.