Population III stars are predicted to be extremely massive and hot. These stars have short lifespans as they burnout rapidly. Nevertheless, simulations of the formation of Population III stars show that in the initial mass distribution of these stars, the least massive ones may be less massive than the Sun. If Population III stars with less than 0.8 times the Sun’s mass formed in the early universe, the lower mass and correspondingly longer lifespans means that they should still be present today.
Carbon and oxygen tend to be in the gas phase while iron tends to be in the dust phase. If low-mass Population III stars are only polluted by gas accretion, then they are expected to be enriched in carbon and oxygen, and depleted in iron. Such a chemical signature is similar to a category of stars known as carbon-enhanced metal poor (CEMP) stars. CEMP stars are some of the most metal-poor stars known and some fraction of them might turn out to be Population III stars that have been polluted by gas accretion.
Jarrett L. Johnson (2015), “The chemical signature of surviving Population III stars in the Milky Way”, arXiv:1411.4189 [astro-ph.GA]