In book 4 Dr. Brown addresses the Jewish proof of fallacy/error/lack of divine inspiration of Jesus and/or the author of Matthew, which Jews often bring from Matthew 23:35. In Matthew 23:35 Jesus refers to Zechariah ben B'rachyah, while it is clear from context that he means to refer to Zechariah ben Yehoyada. Jews point out that obvious textual error in simply referring back to a prior biblical story.
Brown says something that has intrigued as well as bothered me quite a bit, and I am hoping that someone can shed some insight onto the matter.
Brown points out that the Targum on Eichah 2:20 refers as well to the murder of Zechariah- the targum (in accord with the text of that possuk) explicitly says that it is referring to the murder of Zechariah in the temple. The thing is, Brown points out, that the targum refers to zechariah bar iddo. And Zechariah ben berachiah ben iddo is the other zechariah- the wrong zechariah- the one that Matthew refers to. Per the klal of beni banim harei hein kbanim (Brown doesnt say this exact point), it seems correct to say that zechariah bar iddo is zechariah ben berachiah. Brown does point out that the book of ezra refers to zechariah ben berachia as zechariah bar iddo, which would lend support to the fact that when the targum refers to zechariah bar iddo it is referring to zechariah ben berachiah.
Now contextually, however, we are referring to the murder in the temple of someone who was both a navi and a kohein, and we are identifying this individual as zechariah. The only person mentioned in tanach (or elsewhere in jewish tradition at all, to my knowledge), is zechariah ben yehoyadah.
So the targum seems to be referring to zechariah ben yehoyada, but yet is calls him zecharyah bar iddo; which seems to be synoymous with zechariah ben berachyah. Thus, Dr. Brown contends that we have an authentic Jewish source stating the same thing tha the author of Matthew states. Brown therefore says that we will need to either recognize error in both Matthew and the Targum, or speculate that both Matthew and the targum were correct but referring to another event (the murder of zechariah ben berachyah in the temple), an event for which we have no documentation or support. I believe Brown has a third possibility too, but I dont remember it at the moment.
In any event, this seems to me to be a fair contention on Browns part. So I did a lot of thorough research in the attempt to resolve this. Firstly, I verified the starting point of Browns argument by looking up the targum in three different mikraos gedolos nach sets on eichah. They all were in agreement with each other, and Brown definately quoted the text accurately. I looked up all the meforshim in the mikraos gedolos sets that I had available. I also looked up the torah temimah and his novella on this possuk. I looked up the two or three references (I dont remember now if there were two or three- but one was in sanhedrin and one was in yuma or brachos- I forget now) to this interpretation of eichah 2:20 (interpretation regarding zecharyah being murdered in the temple, i mean) which are mentioned in the talmud bavli. I looked up the rashi and maharsha on each of these, as well as the ein yaakov, and the nosei keilim on the daf. I looked up the two instances in the midreash rabbah, two instances in the yalkut shimoni, and one instance in the torah kohanim (this was a while ago, but I think my memory serves me correct about this) which I became aware of as referring to this concept, as well. All of the references which I found either did not speak of this point (ie- I dont think that I found any ein yaakov on any of this, if I remember correctly), or explicitly stated the point and applied it explicitly to zecharyah ben yehoyadh (as for example rashi in the gemara does). It could be that some stated the pont and just mentioned zecharyah without further clarification of which zecharyah they were referring to, but again, my memory alludes me about this (it was about two months ago that I looked into this). Point being that all the sources that I found which made reference to this point explicitly applied it to zecharyah ben yehoyadah- except for this one targum- which applied it to zecharyah bar iddo (ben berachya, I would say). This, if anything served to reinforce Brown's point that the targum strangely seems to refer to the wrong Zecharyah, as does Matthew.
I did not become aware of any talmud yerushalmi or tannaitic works (mishnah, tosefta, any of the mesechtos ketanos, pirkei drabbi eliezer, tanna dbei eliyahu, or zohar either), or other midrashim, which make reference to this concept in reference to this possuk.
I took out a concordance and looked up iddo- I did not find any reference to iddo in tanach which bore any relation to zecharyah ben yehoyadah either- so I dont see how zecharyah bar iddo can be construed as a reference to zecharyah ben yehoyadah.
The best answer to Brown's point that I myself could come up with was the fact that chazal tell us that there is no targum on kesuvim. But to try to claim that as an answer, and thus discount the targum on eichah- first of all I dont think that would be a kosher jewish answer within the pale of Torah Judaism, and even so, it seems to me that that is for all intensive purposes conceding to Brown's pont.
This question is relevant even if we leave Matthew out of the picture- for it questions the validity of our mesorah.
So, I turn the question over to you guys, can someone please justify the statement that is found in the targum on eichah 2:20 that states that the kohein and navi that was killed in the beis hamikdash is zecharyah bar iddo?
Thanks.

