Nice pictures Sylvia. They do bring back fond memories. Pulmonias are only found in Mazatlan, having been blocked by taxi unions everywhere else. They are very fun to ride in.
The troubles in Mazatlan actually began in the summer of 2008 when there was a spate of murders including one on the local public golf course. In September of 2008, a large group of gunmen were arrested after taking a wrong turn after a botched payroll robbery and ending up surrounded on the rocks near Playa Bruja. Apparently these guys were one of the gangs fighting over Mazatlan because things quieted down considerably after that until December of 2009 when a police officer was killed in broad daylight near the Mega store, six people were shot at a nightclub called Heradurra soon afterward and "narco-banners" began appearing. That ushered in the current round of problems which have not really increased very much this year over last year, but show absolutely no sign of stopping either.
I would still go to Mazatlan and I am sure I would still have a great time. However I don't sugar coat or minimize what is going on there.