No electrocuted thief found yet...There's apparently been a series of Prius battery pack thefts in California (especially San Francisco). The criminals apparently know what they're doing because, well, their electrocuted bodies haven't been found near to a Prius with a busted window and opened trunk yet. As the mechanic shows in the video below, getting to a Prius battery isn't as simple as popping open the trunk and walking away with it. They weight about 150 pounds (this isn't like stealing a 3 pound car stereo), and to get them out quickly you have to cut through multiple cables and bolts. It is estimated that the thieves can do the job in about 20 minutes.
According to an ABC news report, there's been a "rash" of similar thefts in San Francisco lately. It's hard to know if it's a case of a handful of thefts committed by the same thief or thieves being amplified by the media, or if there's really been an overall increase, possibly because second generation Prius hybrids are starting to get older and there must be increasing demand for replacement battery pack.
New batteries, when out of warranty, cost about $2,500 in the US, but that varies by market (they're cheaper in the UK at £800). Repairing all the damage done by a thief can add quite a bit to the bill, though.
According to John Nashed, who had his Prius broken into, "We looked on Craigslist, the batteries are going around $900 to a $1,000"—a lot of money for a 20-minute smash-and-grab job, and, for a prospective buyer, a good discount over an official replacement battery. Prius owners should of course be very wary of buying a used battery from the black or grey market; you have no idea how many miles have been driven on the battery. (source)
This garage has a few suggestions to make the battery harder to steal: "As an anti-theft measure we can replace the 12mm bolts with tamper-proof ones and shield the harnesses with sheet metal. If it slows thieves down, that's enough."
If you're curious, here's what you would do to legitimately remove a Prius battery without breaking everything: