[van_exel_fan]

When straightforward players raise 5x BB they almost always have JJ or AK. This is because they do not like playing these hands post-flop but they are strong pre-flop hands. If he has JJ maybe he thinks you are just picking up the pot on the turn so he is calling (w/ 1000 chip and 500 chip). He said call 3 seconds later because he wanted to clarify that he was just calling using 1500 in chips. If he has AK he probably feels like he is sitting on a monster so doesn't care if it is a call or raise. Call turn and lead river.