[Sir Napsalot]

Homemade (unsophisticated) or not, I read somewhere the detonator part still need professional training, hence the elder brother's 6-month trip.

Also probably the trial run. Good find, Jim.

[Texas Fossil]

I assume they had an electronic timer to trigger a blasting cap. Read somewhere they identified manufacturer of the battery that was used.

Short leads on a electric blasting cap could have been used with an internal timer in the bomb. That would reduce stray pickup on wires in the system. Have heard that we used generator systems in sandpile to detonate some of their IEDs.

Hand placing the explosive has some risk for the one who delivers It.