First let us cite the incident as recorded by Imam Ahmed:
Ibn Abbas said: ‘Once Umar was informed that Samra sold alcohol. Umar said: “May Allah curse Samra! Allah’s messenger said: ‘May Allah curse the Jews for Allah had forbidden them to eat the fat of animals but they melted it and sold it.’’
Musnad Ahmed bin Hanbal, Volume 1 page 25 Tradition 170
Now, Bukhari has also recorded this very tradition from his master Humaidi but being a staunch biased Sahaba worshipper, he redacted the name of Samra, we hence read this tradition in Sahih Bukhari in the following manner:
Narrated al-Humaidi from Sufyan from Amr bin Dinar from Tawoos from Ibn ‘Abbas:
Once ‘Umar was informed that a certain man sold alcohol. ‘Umar said, “May Allah curse him! Doesn’t he know that Allah’s Apostle said, ‘May Allah curse the Jews, for Allah had forbidden them to eat the fat of animals but they melted it and sold it.”
Sahih Bukhari ,Volume 3, Book 34, Number 426 page 234
When we read this tradition from the original source from whence Imam Bukhari had taken it i.e. from Musnad al-Humaidi, we find the name of Sahabi Samra is cited:
حدثنا سفيان حدثنا عمرو بن دينار قال: أخبرني طاووس سمع ابن عباس يقول: بلغ عمر بن الخطاب أن سمرة باع خمراً ، فقال : قاتل الله سمرة ، ألم يعلم أن رسول الله صلى الله عليه وسلم قال: لعن الله اليهود حرمت عليهم الشحوم فجملوها فباعوها
Narrated Sufyan from Amro bin Dinar from Tawoos from Ibn Abbas who said:
Once ‘Umar was informed that Samra sold alcohol. ‘Umar said, “May Allah kill Samra! Doesn’t he know that Allah’s messenger said, ‘May Allah curse the Jews, for Allah had forbidden them to eat the fat of animals but they melted it and sold it.”
Musnad al-Humaidi, Volume 1 page 17 Tradition 15