How did mrs.Van Dann and Mr.Van Dann die?

mr.vann dann was gassed in 1944. Ms.vann dann died during or after a march. mr.vann dann was gassed in 1944. Ms.vann dann died during or after a march. mr.vann dann was gassed in 1944. Ms.vann dann died during or after a march. mr.vann dann was gassed in 1944. Ms.vann dann died during or after a march.