An order was given for Umaiya bin Khalaf Abi Safwan to be killed for persecuting Muslims. He was so evil, he used to torture Muslims. Bilal (ra) was one of his victims. In the end he got killed.
Abdul Aziz As Shanawi
TORTURE AT THE HANDS OF THE QURAISH
No group of people was tortured more severely than slaves; for the most part, others had at least some form of protection or some status in society to prevent them from being severely tortured. Abd since Bilal was a slave, Quraish’s chiefs had no qualms about torturing him: he had no protector or patron from Quraish’s chiefs, and he was not a relative of anyone from the Quraish. Umayyah bin Khalaf would make Bilal lie on his face in the hot sands of the desert; he would then place a heavy stone over his body, allowing it to heat in the sun and crush Bilal with its weight. Yet Bilal remained patient and steadfast throughout such torture sessions. Umayyah bin Khalaf would say to him, ‘Disbelieve in the Lord of Muhammad,’ and that is what it would have taken to end the pain and torture, but Bilal refused. He simply replied, ‘The One (true God), the One (true God).’ Later, when he was asked why he would give that particular answer, Bilal said that of all the answers he gave to his torturers, it was the one that made them most angry. 
Shaykh Allama Shibli Numani
The arch-enemy of the Prophet (p), Umayya Ibn Khalaf had also joined the Quraish army. Sometime back, Abd al-Rahman Ibn Auf had promised him safety if he came to Medina. The battle should have been a nice opportunity for the Muslims to be revenged upon this enemy of God. But to honour a pledge was the hall mark of the Muslim. Abd al-Rahman did his best to let Umayya made good his escape. He took him to a hill, but was detected by Bilal who let the Ansar know of it. In an instant some Muslims fell upon him. Abd al-Rahman pushed forward Umayya’s sons to shield him, and he was slain. But the assailants were not satisfied and advanced towards Umayya himself. Abd al-Rahman asked him to lie down, and when he had done so, Abd al-Rahman bent down over him to protect him against attack. But the assailants reached out their hands from under the legs of Abd al-Rahman and despatched him. Abd al-Rahman himself was severely wounded in the leg which remained scarred for a long time. 
Further attestation is that he was involved in wars against the Muslims community in the following authentic Hadith:
It has been narrated on the authority of Anas that when (the news of) the advance of Abu Sufyan (at the head of a force) reached him. the Messenger of Allah held consultations with his Companions. The narrator said: Abu Bakr spoke (expressing his own views), but he (the Holy Prophet) did not pay heed to him. Then spoke ‘Umar (expressing his views), but he (the Holy Prophet) did not pay heed to him (too). Then Sa’d b. ‘Ubada stood up and said: Messenger of Allah, you want us (to speak). By God in Whose control is my life, if you order us to plunge our horses into the sea, we would do so. If you order us to goad our horses to the most distant place like Bark al-Ghimad, we would do so. The narrator said: Now the Messenger of Allah called upon the people (for the encounter). So they set out and encamped at Badr. (Soon) the water-carriers of the Quraish arrived. Among them was a black slave belonging to Banu al-Hajjaj. The Companions of the Messenger of Allah caught him and interrogated him about Abu Sufyan and his companions. He said: I know nothing about Abu Sufyan, but Abu Jahl, Utba, Shaiba and Umayya b. Khalaf are there. … The narrator said: Then the Messenger of Allah said: This is the place where so and so would be killed. He placed his hand on the earth (saying) here and here; (and) none of them fell away from the place which the Messenger of Allah had indicated by placing his hand on the earth. – (Sahih Muslim Book 19, Hadith 4394)
The above narration shows that Umayya B. Khalaf was involved in the batlle of Badr against the Muslims.
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 The Ministers around the Prophet [Mataba Dar-us-salam, 2004] By Abdul Aziz As Shanawi, Page 131 – 132
 Sirat -un- Nabi By Shaykh Allama Shibli Numani – Volume 2 page 22