Is it true that D.O. school is longer than M.D. school?

I think I've read this a couple of times before on here (that D.O. school might be one year longer compared to M.D. school), but it could be that the person who said it didn't know what they were talking about. As far as I know, both programs are generally four years.

I know that the length of residencies vary according to specialty, but let's imagine the following scenario: Suppose one student wants to be a D.O. internist, and another student wants to be an M.D. internist. If they both start medical school at the same time, will they also finish medical school and their residency programs at the same time? If not, how much of a gap in time will there be?

Preferably, I'd like to hear from allopathic and/or osteopathic students/doctors, or anyone who definitely knows the answer to this question. Thanks.

There should not be any gap. Any difference in time of finishing school would be due to personal differences, residency lengths, etc. M.D./D.O. are equivalent here.