is AC current more lethal

Answer 1

Neither, but they do have somewhat different harmful effects. A few examples are:

• DC will tend to make you hold onto the wires giving the shock until someone turns off the power, AC will tend to make you throw yourself away from the wires giving you the shock (this may cause serious physical injuries as you fall on other objects)
• DC will tend to flow through the core tissues of the body making it more likely to reach the heart, AC will tend to flow through the outer tissues making it more likely to cause visible burns
• etc.

Note: these are all tendencies not absolutes, there are obviously exceptions. Also equivalent harmful effects occur at much lower AC RMS current levels than DC current levels, which may give the impression that AC is more harmful than DC.

Answer 2

DC currents are going to be more harmful than AC currents.