Who killed Jesus the Romans or the Jews?

The Jews tried him and sentenced him to death via their own courts and handed him over to the Romans and convinced them to kill him. The Romans did the actual killing.

What's this? Is it thumb-down o'clock?

Jesus was neither killed by the Romans nor the Jews. Jesus was killed by religion. Jesus was plotted and killed by the Pharisees and the priests of the temple of Jerusalem, because Jesus liberated the Jews from their religion.

The roman jews!

Some Romans, supposedly at the behest of some Jews.

Given that any historicity of Jesus is practically non-existent outside of 1st century festival passion plays, and assuming that there was one particular Jesus you are referring to (there were a few Jesus's who came to a grisly end), then the cry from the Jews calling for the pardon of Bar Abba (Son of the Father), suggests that despite the Jews' plea of mercy for Jesus, the infamous tyrant Pontius Pilatus - not being the sort of man to acquiesce to the "common rabble", was quite happy to send the poor sod to his death wthout a moment's murmur.

The 95-96 Bulls killed that muthafucka

the romans put Him on the cross, the jews told them to.

According to the Bible...

the Jewish religious leaders in Jerusalem had Jesus arrested...

- and tried him...

- and upon finding him guilty handed him over to the Romans, pressing charges...

the Romans tried him...

- and found him guilty...

- and sentenced him to death

- and executed him

So: the Romans executed Jesus.