Per CNN text Hamas leaders did not know or approve of kidnapped Israeli teens.

[Uncle Joe]

http://www.cnn.com/2014/08/22/world/meast/mideast-crisis/index.html?hpt=hp_t1

Hamas admits its men abducted Israeli teens, says its leaders didn't know

Gaza (CNN) -- A Hamas official admitted Friday that militants from his group abducted three Israeli teens in the West Bank in June, but the official said the kidnappers did not tell their leaders about the action.

(snip)

Saleh Aruri, a Hamas Political Bureau member, said in a statement from Doha, Qatar, the operation to abduct the teens was not approved by the Hamas leadership or its military wing, the Qassam Brigades.

"At that time, the Hamas leadership had no knowledge about this group or the operation it had just carried," Aruri said, referring to the abductors. "It turned out later, however, that they were members of Hamas."

(snip)

So according to CNN and the Guardian reports just below, Hamas leadership didn't know or approve of the kidnappings, one senior leader of the al-Qassam Brigades did claim responsibility but the Guardian assigns "alternative motives."

http://www.theguardian.com/world/2014/aug/21/hamas-kidnapping-three-israeli-teenagers-saleh-al-arouri-qassam-brigades

(snip)

His claim has not been supported by any other member of Hamas.

Hugh Lovatt, Israel and Palestine coordinator at the European Council on Foreign Relations, said that while al-Arouri was a significant Hamas figure – serving as the group's most prominent representative in Turkey – the former militant could have an ulterior motive for making his claim.

"Given the timing I would be very suspicious about his claim. I still don't believe Hamas as an organization and its upper echelons sanctioned the kidnappings – something that Israeli intelligence also believes," he said.

Lovatt said that al-Arouri may be trying to claim credit for the actions of others in an attempt to demonstrate his own continued sway in the West Bank and Hamas's ability to hit Israel after failing to secure significant concessions after six weeks of violence in Gaza.

"A second, more remote possibility, is that al-Arouri is telling the truth and that he has operated on his own initiative – a development with very worrying repercussions as it would imply a serious power struggle and splintering within Hamas," he said.

According to Wikipedia the makeup of Hamas and its military wing' the Al-Qassum Brigades is as that of Sinn Fein and the IRA.

http://en.wikipedia.org/wiki/Izz_ad-Din_al-Qassam_Brigades

The Izz al-Din al-Qassam Brigades are an integral part of Hamas. While they are subordinate to Hamas's broad political goals and its ideological objectives, they have a significant level of independence in decision making.[9] In 1997, political scientists Ilana Kass and Bard O'Neill described Hamas's relationship with the Brigades as reminiscent of Sinn Féin's relationship to the military arm of the Irish Republican Army and quoted a senior Hamas official: "The Izz al-Din al-Qassam Brigade is a separate armed military wing, which has its own leaders who do not take their orders [from Hamas] and do not tell us of their plans in advance."[10] Carrying the IRA analogy further, Kass & O'Neill stated that the separation of the political and military wings shielded Hamas' political leaders from responsibility for terrorism while the plausible deniability this provided made Hamas an eligible representative for peace negotiations as had happened with Sinn Féin's Gerry Adams.[11]

The fighters' identities and positions in the group often remain secret until their death; even when they fight against Israeli incursions, all the militants wear a characteristic black hood on which the group's green headband is attached. The Izz ad-Din al-Qassam Brigades operate on a model of independent cells and even high-ranking members are often unaware of the activities of other cells. This allows the group to consistently regenerate after member deaths. During the al-Aqsa intifada, the leaders of the group were targeted by numerous airstrikes that killed many members, including Salah Shahade and Adnan al-Ghoul. The current leader of the brigades, Mohammed Deif, remains at large and is said to have survived at least five assassination attempts.[12]

The CNN text also states that one day after Israel was able to target and kill three senior leaders of the Al-Qassam Brigades, Hamas executed 18 Israeli "informants."

So what are the "alternative motives" as mentioned by the Guardian?

I believe Hamas was beginning to take the path of moderation first exhibited in its agreement and signing with Fatah to form a unity government in May and June of this year, they were going to hold elections which ultimately would increase the chances of a successful peace agreement being negotiated with Israel.

Extremist elements of the Al-Qassam Brigades didn't want this to happen, they were committed to the struggle so they kidnapped and murdered the three Israeli teens in the hopes that Netanyahu would respond in the way he did.

The successful targeting and killing of the three senior members of the Al-Qassam Brigades and subsequent execution of 18 "informants" may be a sign that the last paragraph of the Guardian text which I posted above may be on the money.