I'm solving some excercises on magnetostatics, and encounterded this on which i'm having some trouble. Given a particle of magnetic dipole moment $\mathbf{m}$, show that its current density is given as $\mathbf{J} = \left( \mathbf{m} \times \nabla \right) \delta \left( \mathbf{r} - \mathbf{r}_{0} \right)$, where $\mathbf{r}_{0}$ is the vector position of the particle.
I started from the stationary Ampere's law, given that the magnetic field $\mathbf{B}_{m}$ is due only by the magnetic dipole moment
$$ \nabla \times \mathbf{B}_{m} \left( \mathbf{r} - \mathbf{r}_{0} \right) = \mu_{0} \; \mathbf{J} \left( \mathbf{r} \right)$$
So that
$$ \boxed{\mathbf{J} \left( \mathbf{r} \right) = \frac{1}{\mu_{0}} \nabla \times \mathbf{B}_{m} \left( \mathbf{r} - \mathbf{r}_{0} \right)} \; \; \; \; (1)$$
Now, it terms of the magnetic dipole moment, the corresponding magnetic field is given as
$$ \boxed{\mathbf{B}_{m} \left( \mathbf{r} - \mathbf{r}_{0} \right) = \frac{\mu_{0}}{4\pi} \left[ \frac{\mathbf{m}\cdot\left(\mathbf{r} - \mathbf{r}_{0}\right)}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{5}} \left( \mathbf{r} - \mathbf{r}_{0} \right) - \frac{\mathbf{m}}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{3}} \right]} \; \; \; \; (2) $$
Replacing, then, (2) into (1)
$$ \mathbf{J}\left( \mathbf{r} \right) = \frac{1}{4 \pi} \nabla \times \left( \frac{\mu_{0}}{4\pi} \left[ \frac{\mathbf{m}\cdot\left(\mathbf{r} - \mathbf{r}_{0}\right)}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{5}} \left( \mathbf{r} - \mathbf{r}_{0} \right) - \frac{\mathbf{m}}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{3}} \right] \right) $$
$$ = \frac{1}{4 \pi} \left[ \nabla \times \left( \frac{\mathbf{m}\cdot\left(\mathbf{r} - \mathbf{r}_{0}\right)}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{5}} \left( \mathbf{r} - \mathbf{r}_{0} \right) \right) - \nabla \times \left( \frac{\mathbf{m}}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{3}} \right) \right] $$
$$ = \frac{1}{4 \pi} \left[ \nabla \left( \frac{\mathbf{m}\cdot\left(\mathbf{r} - \mathbf{r}_{0}\right)}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{5}} \right) \times \left( \mathbf{r} - \mathbf{r}_{0} \right) + \frac{\mathbf{m}\cdot\left(\mathbf{r} - \mathbf{r}_{0}\right)}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{5}} \nabla \times \left( \mathbf{r} - \mathbf{r}_{0} \right) \right. $$
$$ \left. - \nabla \left( \frac{\mathbf{1}}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{3}} \right) \times \mathbf{m} - \frac{\mathbf{1}}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{3}} \nabla \times \mathbf{m} \right] $$
Now, as $\nabla \times \left( \mathbf{r} - \mathbf{r}_{0} \right)=0$ and $\nabla \times \mathbf{m}=0$
$$ \boxed{\mathbf{J}\left( \mathbf{r} \right) = \frac{1}{4 \pi} \left[ \nabla \left( \frac{\mathbf{m}\cdot\left(\mathbf{r} - \mathbf{r}_{0}\right)}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{5}} \right) \times \left( \mathbf{r} - \mathbf{r}_{0} \right) - \nabla \left( \frac{\mathbf{1}}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{3}} \right) \times \mathbf{m} \right]} \; \; \; \; (3) $$
Now, by components
$$ \left( \nabla \left[ \frac{\mathbf{m}\cdot\left(\mathbf{r} - \mathbf{r}_{0}\right)}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{5}} \right] \right)_{i} = \partial_{i} \left( \frac{m_{j} (x_{j} - x^{0}_{j}) }{ [(x_{l} - x^{0}_{l})(x_{l} - x^{0}_{l})]^{5/2} } \right)$$
$$ = m_{j} \left\{ \frac{1}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {5}} \partial_{i} (x_{j} - x^{0}_{j}) + (x_{j} - x^{0}_{j}) \partial_{i} [(x_{l} - x^{0}_{l})(x_{l} - x^{0}_{l})]^{-5/2} \right\} $$
$$ = m_{j} \left\{ \frac{\delta_{ij}}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {5}} - \frac{5}{2}\frac{1}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {7}}2(x_{l} - x^{0}_{l})\delta_{il}(x_{j} - x^{0}_{j}) \right\} $$
$$ = m_{j} \left\{ \frac{\delta_{ij}}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {5}} - 5\frac{(x_{i} - x^{0}_{i})(x_{j} - x^{0}_{j})}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {7}} \right\} $$
$$ = \frac{m_{i}}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {5}} - 5 \frac{m_{j} (x_{j} - x^{0}_{j})}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {7}}(x_{i} - x^{0}_{i}) $$
$$ \boxed{\left( \nabla \left[ \frac{\mathbf{m}\cdot\left(\mathbf{r} - \mathbf{r}_{0}\right)}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{5}} \right] \right)_{i} = \left[ \frac{\mathbf{m}}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {5}} - 5 \frac{\mathbf{m} \cdot (\mathbf{r} - \mathbf{r}_{0}) }{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {7}}(\mathbf{r} - \mathbf{r}_{0}) \right]_{i}} \; \; \; \; (4) $$
Likewise
$$ \left( \nabla \left[ \frac{1}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{3}} \right] \right)_{i} = \partial_{i} [(x_{j} - x_{j}^{0})(x_{j} - x_{j}^{0})]^{-3/2} $$
$$ = -\frac{3}{2} \frac{1}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {5}}2(x_{j} - x_{j}^{0})\delta_{ij} $$
$$ = -3 \frac{1}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {5}} (x_{i} - x_{i}^{0}) $$
$$ \boxed{\left( \nabla \left[ \frac{1}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{3}} \right] \right)_{i} = \left( -3 \frac{1}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {5}} (\mathbf{r} - \mathbf{r}_{0}) \right)_{i}} \; \; \; \; (5) $$
Replacing (4) and (5) into (3)
$$ \mathbf{J}\left( \mathbf{r} \right) = \frac{1}{4 \pi} \left[ \left( \frac{\mathbf{m}}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {5}} - 5 \frac{\mathbf{m} \cdot (\mathbf{r} - \mathbf{r}_{0}) }{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {7}}(\mathbf{r} - \mathbf{r}_{0}) \right) \times \left( \mathbf{r} - \mathbf{r}_{0} \right) - \left( -3 \frac{1}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {5}} (\mathbf{r} - \mathbf{r}_{0}) \right) \times \mathbf{m} \right] $$
And, because $\left( \mathbf{r} - \mathbf{r}_{0} \right) \times \left( \mathbf{r} - \mathbf{r}_{0} \right) = 0$
$$ \mathbf{J}\left( \mathbf{r} \right) = \frac{1}{4 \pi} \left[ \left( \frac{\mathbf{m}}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {5}} \right) \times \left( \mathbf{r} - \mathbf{r}_{0} \right) + 3 \frac{1}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {5}} (\mathbf{r} - \mathbf{r}_{0}) \times \mathbf{m} \right] $$
$$ \mathbf{J}\left( \mathbf{r} \right) = \frac{1}{4 \pi} \left(-2 \left( \frac{\mathbf{m}}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {5}} \right) \times \left( \mathbf{r} - \mathbf{r}_{0} \right) \right)$$
$$ \boxed{\mathbf{J}\left( \mathbf{r} \right) = -\frac{1}{2 \pi} \mathbf{m} \times \frac{\left( \mathbf{r} - \mathbf{r}_{0} \right)}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {5}}} $$
Here is where i'm stuck. I'm aware of the identity
$$ \nabla \cdot \left[ \frac{\mathbf{r} - \mathbf{r}_{0}}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^{3}} \right] = 4 \pi \delta (\mathbf{r} - \mathbf{r}_{0})$$
So, assuming that the answer presented in the statement is true (and that my calculations were correct), then it must be true that
$$ -\frac{1}{2 \pi} \frac{\left( \mathbf{r} - \mathbf{r}_{0} \right)}{\left| \mathbf{r} - \mathbf{r}_{0} \right|^ {5}} = \nabla \delta \left( \mathbf{r} - \mathbf{r}_{0} \right) $$
but, if this is indeed true, i'm not sure how to prove this.
Thanks in advance for any help!