Ruling on building a mosque or addition to a mosque with haraam wealth
Question

                Can a masjid or its extention for a community hall adjacent to masjid for mulity purpose where jumah salah in ramadan and eid prayer are planned, be built with donations which are not halal,ins-pite the fact that the masjid management have knowledge of it.
Praise be to Allah.Haraam 
    wealth is either haraam in and of itself, or it is haraam because of the 
    manner in which it was acquired. 
If the 
    wealth is haraam in and of itself, such as extorted and stolen wealth, this 
    it is not permissible for anyone of make use of it if he knows that it was 
    stolen from so and so, rather it must be returned to its owner. 
The way in 
    which to repent from extorting this money is to return it to its owner. It 
    is not sufficient for the robber to donate it for building a mosque when he 
    is able to return it to its owner. 
But if he is 
    not able to return it to its owner (such as money that has been stolen by 
    some oppressive governments from the people), then there is nothing wrong 
    with spending it on the public interests of the Muslims, which includes 
    building mosques. 
Shaykh 
    al-Islam Ibn Taymiyah (may Allaah have mercy on him) said in al-Siyaasah 
    al-Shar’iyyah (p. 35): 
If the 
    wealth was taken unlawfully and he is unable to return it to its owners, 
    like much of the government wealth (which has been stolen by the ruler), 
    then helping to spend this wealth in things that serve the interests of the 
    Muslims, such as guarding the borders, covering the expenses of the troops 
    and so on is a kind of helping in righteousness and piety, because what the 
    ruler should do with this money – if he cannot find its owners and return it 
    to them or to their heirs – is to spend it on the interests of the Muslims, 
    as well as repenting if he is the one who did wrong. This is the view of the 
    majority of scholars such as Maalik, Abu Haneefah, and Ahmad. It was also 
    narrated from more than one of the Sahaabah and this is what is indicated by 
    the shar’i evidence. 
Even if 
    someone else took it unlawfully, then he must still do that with it. End 
    quote. 
As for 
    wealth that is haraam because of the way in which it was acquired, this is 
    wealth which a person earned in a haraam way, such as selling alcohol and 
    dealing in riba, or payments for singing and prostitution and so on. This 
    wealth is haraam only for the one who acquired it. If someone else takes it 
    from him in a permissible manner, there is no sin in that, such as if he 
    were to donate it to build a mosque, or to give it as wages to a worker who 
    did a job for him, or he spends it on his wife or children – it is not 
    haraam for them to benefit from it, rather it is haraam only for the one who 
    acquired it in a haraam manner.  
The way to 
    repent from acquiring haraam wealth is to get rid of it, and to spend it on 
    charitable causes, which include building mosques. 
Al-Nawawi 
    (may Allaah have mercy on him) said in al-Majmoo’ (9/330): 
Al-Ghazaali 
    said: If he has any haraam wealth and he wants to repent and get rid of it – 
    if it has a particular owner then he must give it to him or to his 
    representative. If he is dead then he must give it to his heir. If it 
    belongs to someone who he does not know and he has no hope of finding him, 
    then he should spend it on the public interests of the Muslims, such as 
    bridges, border posts and mosques, and other things which the Muslims share. 
    Otherwise he may give it in charity to poor people. This is what al-Ghazaali 
    said and what others of our companions mentioned, and it is as they said, 
    because it is not permissible to destroy this wealth or throw it into the 
    sea. There is no other option but to spend it on the Muslims’ interests. And 
    Allaah, may He be glorified and exalted, knows best. 
Shaykh Ibn 
    ‘Uthaymeen (may Allaah have mercy on him) was asked about the ruling on 
    praying in a mosque that was built with haraam money. He replied: 
It is 
    permissible to pray in it and there is no sin in that, because the one who 
    built it from haraam wealth may have intended by building it to rid himself 
    of the haraam wealth that he had acquired, in which case it was permissible 
    for him to build this mosque, if his intention was to get rid of haraam 
    wealth. But getting rid of haraam wealth is not only done by building 
    mosques, rather if a person spends that on any charitable project, he has 
    achieved the same aim. End quote. 
Majmoo’ 
    Fataawa Ibn ‘Uthaymeen, 12/question no. 304. See 
    also al-Sharh al-Mumti’, 4/344. 
And Allaah 
    knows best.