For a prime number $$\ell $$
ℓ
we say that an oriented pro-$$\ell $$
ℓ
group $$(G,\theta )$$
(
G
,
θ
)
has the Bogomolov–Positselski property if the kernel of the canonical projection on its maximal $$\theta $$
θ
-abelian quotient $$\pi ^{\mathrm {ab}}_{G,\theta }:G\rightarrow G(\theta )$$
π
G
,
θ
ab
:
G
→
G
(
θ
)
is a free pro-$$\ell $$
ℓ
group contained in the Frattini subgroup of G. We show that oriented pro-$$\ell $$
ℓ
groups of elementary type have the Bogomolov–Positselski property (cf. Theorem 1.2). This shows that Efrat’s Elementary Type Conjecture implies a positive answer to Positselski’s version of Bogomolov’s Conjecture on maximal pro-$$\ell $$
ℓ
Galois groups of a field $$\mathbb {K}$$
K
in case that $$\mathbb {K}^\times /(\mathbb {K}^\times )^\ell $$
K
×
/
(
K
×
)
ℓ
is finite. Secondly, it is shown that for an $$H^\bullet $$
H
∙
-quadratic oriented pro-$$\ell $$
ℓ
group $$(G,\theta )$$
(
G
,
θ
)
the Bogomolov–Positselski property can be expressed by the injectivity of the transgression map $$d_2^{2,1}$$
d
2
2
,
1
in the Hochschild–Serre spectral sequence (cf. Theorem 1.4).