I guess verify task is colloborative task. In jbpm i don't know whether we can define colloborative task. But you need to modify your workflow such way that you can still achieve the same functionality.
Use Fork and join for your "verify task" create two similar structured tasks and assign to two verifier users. or if you want that let first person verify the task and based on inputs(like comments) create similar structured task and assign to 2nd person and place this two task one after other(sequential flow not parallel flow).