Maybe, and maybe not.
I'm sure that this was not the first baptism of this sort performed in this church, and I would even go so far as to bet that the electrical system in this church was designed with Ground Fault Interrupters (GFI) to handle this type of use.
So what went wrong with the wiring to cause the GFIs to fail to trip? Has the possibility of homicide been considered? There is more to this story than is in this newspaper article.
As a live sound engineer, I thought I should try to clear a few things up. First of all, a microphone is typically wired directly to the input of a mixing console, via a snake (bundled microphone cables) or in-wall microphone cables. The microphone goes to the console, not to a wall outlet. The current that electrocuted the pastor was almost certainly 48-volt "phantom power". Phantom power is sent from the mixing console to power certain types of microphones (condensers). This is typically switchable on mixers - you can turn phantom power on or off. Most handheld vocal microphones are "dynamic" microphones and do not have any need for phantom power. But most low- and mid-cost mixers only allow switching of phantom power "globally" - meaning for all channels (microphones) at the same time, rather than the more expensive option of switching "per channel". So if -any- of the church's microphones require phantom power, it would have been turned on, and likely turned on to -all- microphones. Normally this is not a problem, as dynamic microphones simply ignore the phantom power. It can, however, be a danger in certain situations.
For example, if the sound system had a 60 hertz "ground loop" hum problem, one (unsafe) solution is to put "ground lift" devices on power cables at the wall outlet. These are the little grey plugs which take a three-prong (grounded) plug and turn it into a two-prong (ungrounded) plug. It sometimes fixes a hum problem, but it removes the chassis (safety) ground from the equipment to which it is attached. Combine a missing ground, 48V phantom power, and a pastor holding a microphone while standing in water, and you can end up with a problem.