private Thread searchThreadsInSubGroup(final String threadName, final ThreadGroup group, final int level) {
		ThreadGroup[] groups = new ThreadGroup[group.activeGroupCount() * 2];
		int numGroups = group.enumerate(groups, false);

		Thread thread = null;
		for (int i = 0; i < numGroups && thread == null; i++) {
			thread = searchThreadsInGroup(threadName, groups[i], level + 1);
		}
		return thread;
	}