She said, "Ruby`s clothes caught fire while she was cooking."

She said that Ruby`s clothes had caught fire while she is cooking

She said that Ruby`s clothes had caught fire while she had been cooking

She said that Ruby`s clothes have caught fire while she was cooking

She says that Ruby`s clothes had caught fire while she is cooking

Catch fire means آگ لگنا

Caught is the second and third form of the verb Catch.