Actually, given similar powder loadings, they'll penetrate less than a "practice" full metal jacket projectile. When a good hollowpoint bullet hits something of substance, it tends to expand broadening the area that pressure is delivered. This plays perfectly into what standard body armor wants i.e. to spread the bullet's force over a large area. It's the difference between hitting a balloon with a needle and a pool ball in coarse terms.
The bullet's expansion actually helps the vest instead of hinder it. A non-expanding FMJ round would tend to penetrate more because it concentrates the force more.
As has been pointed out, conventional "armor penetration" rounds are steel case/steel core. These style of rounds are illegal for sale in handgun loadings, but they are legal for rifle ammo. They're most commonly seen in military and mil-surplus rounds.
To the best of my knowledge, there are no 10mm "AP" rounds that would be available even on a gray market. The 10mm is not an adopted military round so there would be precious little market for it even if someone were to make it. On the other hand, HK has a 10mm SMG that is being picked up, so someone may have such a round available to a military customer.
Even in idealistic terms, however, a handgun is going to have real issues penetrating good body armor even with a steel case and steel core bullet. The FN 5N7 is a notable exception, but the penetrating ammo for it isn't available to the general public and many law enforcement agencies have been extrememly reluctant to issue such weapons and ammo in fear that it will find its way over to the other side of the law.
Can you link the story so we can investigate it, pls?